Commit Graph

589 Commits

Author SHA1 Message Date
Robert Griesemer 322fff8ac8 math/big: use math/bits where appropriate
This change adds math/bits as a new dependency of math/big.

- use bits.LeadingZeroes instead of local implementation
  (they are identical, so there's no performance loss here)

- leave other functionality local (ntz, bitLen) since there's
  faster implementations in math/big at the moment

Change-Id: I1218aa8a1df0cc9783583b090a4bb5a8a145c4a2
Reviewed-on: https://go-review.googlesource.com/37141
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-24 19:19:02 +00:00
Martin Möhrmann 8c6643846e math: speed up and improve accuracy of Pow10
Removes init function from the math package.

Allows stripping of arrays with pre-computed values
used for Pow10 from binaries if Pow10 is not used.
cmd/go shrinks by 128 bytes.

Fixed small values like 10**-323 being 0 instead of 1e-323.

Overall precision is increased but still not as good as
predefined constants for some inputs.

Samples:

Pow10(208)
before: 1.0000000000000006662e+208
after:  1.0000000000000000959e+208

Pow10(202)
before 1.0000000000000009895e+202
after  1.0000000000000001193e+202

Pow10(60)
before 1.0000000000000001278e+60
after  0.9999999999999999494e+60

Pow10(-100)
before 0.99999999999999938551e-100
after  0.99999999999999989309e-100

Pow10(-200)
before 0.9999999999999988218e-200
after  1.0000000000000001271e-200

name        old time/op  new time/op  delta
Pow10Pos-4  44.6ns ± 2%   1.2ns ± 1%  -97.39%  (p=0.000 n=19+17)
Pow10Neg-4  50.8ns ± 1%   4.1ns ± 2%  -92.02%  (p=0.000 n=17+19)

Change-Id: If094034286b8ac64be3a95fd9e8ffa3d4ad39b31
Reviewed-on: https://go-review.googlesource.com/36331
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-22 19:17:04 +00:00
Alexander Döring ffb3b3698c math: add more tests for special cases of Bessel functions Y0, Y1, Yn
Test finite negative x with Y0(-1), Y1(-1), Yn(2,-1), Yn(-3,-1).

Also test the special case Yn(0,0).

Fixes #19130.

Change-Id: I95f05a72e1c455ed8ddf202c56f4266f03f370fd
Reviewed-on: https://go-review.googlesource.com/37310
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-02-22 17:52:15 +00:00
Robert Griesemer 174058038c math/big: define Word as uint instead of uintptr
For compatibility with math/bits uint operations.

When math/big was written originally, the Go compiler used 32bit
int/uint values even on a 64bit machine. uintptr was the type that
represented the machine register size. Now, the int/uint types are
sized to the native machine register size, so they are the natural
machine Word type.

On most machines, the size of int/uint correspond to the size of
uintptr. On platforms where uint and uintptr have different sizes,
this change may lead to performance differences (e.g., amd64p32).

Change-Id: Ief249c160b707b6441848f20041e32e9e9d8d8ca
Reviewed-on: https://go-review.googlesource.com/37372
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-21 19:31:40 +00:00
Robert Griesemer 177dfba112 math/bits: faster OnesCount
Using some additional suggestions per "Hacker's Delight".
Added documentation and extra tests.

Measured on 1.7 GHz Intel Core i7, running macOS 10.12.3.

benchmark                  old ns/op     new ns/op     delta
BenchmarkOnesCount-4       7.34          5.38          -26.70%
BenchmarkOnesCount8-4      2.03          1.98          -2.46%
BenchmarkOnesCount16-4     2.56          2.50          -2.34%
BenchmarkOnesCount32-4     2.98          2.39          -19.80%
BenchmarkOnesCount64-4     4.22          2.96          -29.86%

Change-Id: I566b0ef766e55cf5776b1662b6016024ebe5d878
Reviewed-on: https://go-review.googlesource.com/37223
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-19 18:50:48 +00:00
Martin Möhrmann 6cfc3b25e9 math: protect benchmarked functions from being optimized away
Add exported global variables and store the results of benchmarked
functions in them. This prevents the current compiler optimizations
from removing the instructions that are needed to compute the return
values of the benchmarked functions.

Change-Id: If8b08424e85f3796bb6dd73e761c653abbabcc5e
Reviewed-on: https://go-review.googlesource.com/37195
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-18 17:00:59 +00:00
Robert Griesemer a4a3d63dbe math/bits: added benchmarks for Leading/TrailingZeros
BenchmarkLeadingZeros-8      	200000000	         8.80 ns/op
BenchmarkLeadingZeros8-8     	200000000	         8.21 ns/op
BenchmarkLeadingZeros16-8    	200000000	         7.49 ns/op
BenchmarkLeadingZeros32-8    	200000000	         7.80 ns/op
BenchmarkLeadingZeros64-8    	200000000	         8.67 ns/op

BenchmarkTrailingZeros-8     	1000000000	         2.05 ns/op
BenchmarkTrailingZeros8-8    	2000000000	         1.94 ns/op
BenchmarkTrailingZeros16-8   	2000000000	         1.94 ns/op
BenchmarkTrailingZeros32-8   	2000000000	         1.92 ns/op
BenchmarkTrailingZeros64-8   	2000000000	         2.03 ns/op

Change-Id: I45497bf2d6369ba6cfc88ded05aa735908af8908
Reviewed-on: https://go-review.googlesource.com/37220
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 23:41:16 +00:00
Robert Griesemer 19028bdd18 math/bits: faster Rotate functions, added respective benchmarks
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3.

benchmark                    old ns/op     new ns/op     delta
BenchmarkRotateLeft-8        7.87          7.00          -11.05%
BenchmarkRotateLeft8-8       8.41          4.52          -46.25%
BenchmarkRotateLeft16-8      8.07          4.55          -43.62%
BenchmarkRotateLeft32-8      8.36          4.73          -43.42%
BenchmarkRotateLeft64-8      7.93          4.78          -39.72%

BenchmarkRotateRight-8       8.23          6.72          -18.35%
BenchmarkRotateRight8-8      8.76          4.39          -49.89%
BenchmarkRotateRight16-8     9.07          4.44          -51.05%
BenchmarkRotateRight32-8     8.85          4.46          -49.60%
BenchmarkRotateRight64-8     8.11          4.43          -45.38%

Change-Id: I79ea1e9e6fc65f95794a91f860a911efed3aa8a1
Reviewed-on: https://go-review.googlesource.com/37219
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 23:40:45 +00:00
Robert Griesemer a12edb8db6 math/bits: faster OnesCount, added respective benchmarks
Also: Changed Reverse/ReverseBytes implementations to use
the same (smaller) masks as OnesCount.

BenchmarkOnesCount-8          37.0          6.26          -83.08%
BenchmarkOnesCount8-8         7.24          1.99          -72.51%
BenchmarkOnesCount16-8        11.3          2.47          -78.14%
BenchmarkOnesCount32-8        18.4          3.02          -83.59%
BenchmarkOnesCount64-8        40.0          3.78          -90.55%
BenchmarkReverse-8            6.69          6.22          -7.03%
BenchmarkReverse8-8           1.64          1.64          +0.00%
BenchmarkReverse16-8          2.26          2.18          -3.54%
BenchmarkReverse32-8          2.88          2.87          -0.35%
BenchmarkReverse64-8          5.64          4.34          -23.05%
BenchmarkReverseBytes-8       2.48          2.17          -12.50%
BenchmarkReverseBytes16-8     0.63          0.95          +50.79%
BenchmarkReverseBytes32-8     1.13          1.24          +9.73%
BenchmarkReverseBytes64-8     2.50          2.16          -13.60%

OnesCount-8       37.0ns ± 0%   6.3ns ± 0%   ~             (p=1.000 n=1+1)
OnesCount8-8      7.24ns ± 0%  1.99ns ± 0%   ~             (p=1.000 n=1+1)
OnesCount16-8     11.3ns ± 0%   2.5ns ± 0%   ~             (p=1.000 n=1+1)
OnesCount32-8     18.4ns ± 0%   3.0ns ± 0%   ~             (p=1.000 n=1+1)
OnesCount64-8     40.0ns ± 0%   3.8ns ± 0%   ~             (p=1.000 n=1+1)
Reverse-8         6.69ns ± 0%  6.22ns ± 0%   ~             (p=1.000 n=1+1)
Reverse8-8        1.64ns ± 0%  1.64ns ± 0%   ~     (all samples are equal)
Reverse16-8       2.26ns ± 0%  2.18ns ± 0%   ~             (p=1.000 n=1+1)
Reverse32-8       2.88ns ± 0%  2.87ns ± 0%   ~             (p=1.000 n=1+1)
Reverse64-8       5.64ns ± 0%  4.34ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes-8    2.48ns ± 0%  2.17ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes16-8  0.63ns ± 0%  0.95ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes32-8  1.13ns ± 0%  1.24ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes64-8  2.50ns ± 0%  2.16ns ± 0%   ~             (p=1.000 n=1+1)

Change-Id: I591b0ffc83fc3a42828256b6e5030f32c64f9497
Reviewed-on: https://go-review.googlesource.com/37218
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 23:40:10 +00:00
Robert Griesemer 4498b68390 math/bits: faster Reverse, ReverseBytes
- moved from: x&m>>k | x&^m<<k to: x&m>>k | x<<k&m
  This permits use of the same constant m twice (*) which may be
  better for machines that can't use large immediate constants
  directly with an AND instruction and have to load them explicitly.
  *) CPUs don't usually have a &^ instruction, so x&^m becomes x&(^m)

- simplified returns
  This improves the generated code because the compiler recognizes
  x>>k | x<<k as ROT when k is the bitsize of x.

The 8-bit versions of these instructions can be significantly faster
still if they are replaced with table lookups, as long as the table
is in cache. If the table is not in cache, table-lookup is probably
slower, hence the choice of an explicit register-only implementation
for now.

BenchmarkReverse-8            8.50          6.86          -19.29%
BenchmarkReverse8-8           2.17          1.74          -19.82%
BenchmarkReverse16-8          2.89          2.34          -19.03%
BenchmarkReverse32-8          3.55          2.95          -16.90%
BenchmarkReverse64-8          6.81          5.57          -18.21%
BenchmarkReverseBytes-8       3.49          2.48          -28.94%
BenchmarkReverseBytes16-8     0.93          0.62          -33.33%
BenchmarkReverseBytes32-8     1.55          1.13          -27.10%
BenchmarkReverseBytes64-8     2.47          2.47          +0.00%

Reverse-8         8.50ns ± 0%  6.86ns ± 0%   ~             (p=1.000 n=1+1)
Reverse8-8        2.17ns ± 0%  1.74ns ± 0%   ~             (p=1.000 n=1+1)
Reverse16-8       2.89ns ± 0%  2.34ns ± 0%   ~             (p=1.000 n=1+1)
Reverse32-8       3.55ns ± 0%  2.95ns ± 0%   ~             (p=1.000 n=1+1)
Reverse64-8       6.81ns ± 0%  5.57ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes-8    3.49ns ± 0%  2.48ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes16-8  0.93ns ± 0%  0.62ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes32-8  1.55ns ± 0%  1.13ns ± 0%   ~             (p=1.000 n=1+1)
ReverseBytes64-8  2.47ns ± 0%  2.47ns ± 0%   ~     (all samples are equal)

Change-Id: I0064de8c7e0e568ca7885d6f7064344bef91a06d
Reviewed-on: https://go-review.googlesource.com/37215
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-17 22:20:28 +00:00
Robert Griesemer 3a239a6ae4 math/bits: fix benchmarks (make sure calls don't get optimized away)
Sum up function results and store them in an exported (global)
variable. This prevents the compiler from optimizing away the
otherwise side-effect free function calls.

We now have more realistic set of benchmark numbers...

Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3.

Note: These measurements are based on the same "old"
implementation as the prior measurements (commit 7d5c003).

benchmark                     old ns/op     new ns/op     delta
BenchmarkReverse-8            72.9          8.50          -88.34%
BenchmarkReverse8-8           13.2          2.17          -83.56%
BenchmarkReverse16-8          21.2          2.89          -86.37%
BenchmarkReverse32-8          36.3          3.55          -90.22%
BenchmarkReverse64-8          71.3          6.81          -90.45%
BenchmarkReverseBytes-8       11.2          3.49          -68.84%
BenchmarkReverseBytes16-8     6.24          0.93          -85.10%
BenchmarkReverseBytes32-8     7.40          1.55          -79.05%
BenchmarkReverseBytes64-8     10.5          2.47          -76.48%

Reverse-8         72.9ns ± 0%   8.5ns ± 0%   ~     (p=1.000 n=1+1)
Reverse8-8        13.2ns ± 0%   2.2ns ± 0%   ~     (p=1.000 n=1+1)
Reverse16-8       21.2ns ± 0%   2.9ns ± 0%   ~     (p=1.000 n=1+1)
Reverse32-8       36.3ns ± 0%   3.5ns ± 0%   ~     (p=1.000 n=1+1)
Reverse64-8       71.3ns ± 0%   6.8ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes-8    11.2ns ± 0%   3.5ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes16-8  6.24ns ± 0%  0.93ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes32-8  7.40ns ± 0%  1.55ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes64-8  10.5ns ± 0%   2.5ns ± 0%   ~     (p=1.000 n=1+1)

Change-Id: I8aef1334b84f6cafd25edccad7e6868b37969efb
Reviewed-on: https://go-review.googlesource.com/37213
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 20:58:12 +00:00
Robert Griesemer ddb15cea4a math/bits: much faster ReverseBytes, added respective benchmarks
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3.

benchmark                     old ns/op     new ns/op     delta
BenchmarkReverseBytes-8       11.4          3.51          -69.21%
BenchmarkReverseBytes16-8     6.87          0.64          -90.68%
BenchmarkReverseBytes32-8     7.79          0.65          -91.66%
BenchmarkReverseBytes64-8     11.6          0.64          -94.48%

name              old time/op  new time/op  delta
ReverseBytes-8    11.4ns ± 0%   3.5ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes16-8  6.87ns ± 0%  0.64ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes32-8  7.79ns ± 0%  0.65ns ± 0%   ~     (p=1.000 n=1+1)
ReverseBytes64-8  11.6ns ± 0%   0.6ns ± 0%   ~     (p=1.000 n=1+1)

Change-Id: I67b529652b3b613c61687e9e185e8d4ee40c51a2
Reviewed-on: https://go-review.googlesource.com/37211
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 19:38:26 +00:00
Robert Griesemer 7d5c003a3a math/bits: much faster Reverse, added respective benchmarks
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3.

name         old time/op  new time/op  delta
Reverse-8    76.6ns ± 0%   8.1ns ± 0%   ~     (p=1.000 n=1+1)
Reverse8-8   12.6ns ± 0%   0.6ns ± 0%   ~     (p=1.000 n=1+1)
Reverse16-8  20.8ns ± 0%   0.6ns ± 0%   ~     (p=1.000 n=1+1)
Reverse32-8  36.5ns ± 0%   0.6ns ± 0%   ~     (p=1.000 n=1+1)
Reverse64-8  74.0ns ± 0%   6.4ns ± 0%   ~     (p=1.000 n=1+1)

benchmark                old ns/op     new ns/op     delta
BenchmarkReverse-8       76.6          8.07          -89.46%
BenchmarkReverse8-8      12.6          0.64          -94.92%
BenchmarkReverse16-8     20.8          0.64          -96.92%
BenchmarkReverse32-8     36.5          0.64          -98.25%
BenchmarkReverse64-8     74.0          6.38          -91.38%

Change-Id: I6b99b10cee2f2babfe79342b50ee36a45a34da30
Reviewed-on: https://go-review.googlesource.com/37149
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 19:38:13 +00:00
Robert Griesemer 81acd308a4 math/bits: expand doc strings for all functions
Follow-up on https://go-review.googlesource.com/36315.
No functionality change.

For #18616.

Change-Id: Id4df34dd7d0381be06eea483a11bf92f4a01f604
Reviewed-on: https://go-review.googlesource.com/37140
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-02-17 19:02:56 +00:00
Shenghou Ma 211102c85f math: fix typos in Bessel function docs
While we're at it, also document Yn(0, 0) = -Inf for completeness.

Fixes #18823.

Change-Id: Ib6db68f76d29cc2373c12ebdf3fab129cac8c167
Reviewed-on: https://go-review.googlesource.com/35970
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-16 22:41:34 +00:00
Robert Griesemer 661e2179e5 math/bits: added package for bit-level counting and manipulation
Initial platform-independent implementation.

For #18616.

Change-Id: I4585c55b963101af9059c06c1b8a866cb384754c
Reviewed-on: https://go-review.googlesource.com/36315
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-02-16 21:54:59 +00:00
Daniel Martí 6910756f9b math/big: simplify bool expression
Change-Id: I280c53be455f2fe0474ad577c0f7b7908a4eccb2
Reviewed-on: https://go-review.googlesource.com/36993
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-14 23:34:25 +00:00
Michael Munday d2fea0447f math/big: fix s390x test build tags
The tests failed to compile when using the math_big_pure_go tag on
s390x.

Change-Id: I2a09f53ff6562ab9bc9b886cffc0f6205bbfcfbb
Reviewed-on: https://go-review.googlesource.com/36956
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-14 19:44:35 +00:00
Josh Bleecher Snyder 785cb7e098 all: fix some printf format strings
Appease vet.

Change-Id: Ie88de08b91041990c0eaf2e15628cdb98d40c660
Reviewed-on: https://go-review.googlesource.com/36938
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-14 02:09:30 +00:00
Michael Munday a524616860 cmd/{asm,internal/obj/s390x}, math: remove emulated float instructions
The s390x port was based on the ppc64 port and, because of the way the
port was done, inherited some instructions from it. ppc64 supports
3-operand (4-operand for FMADD etc.) floating point instructions
but s390x doesn't (the destination register is always an input) and
so these were emulated.

There is a bug in the emulation of FMADD whereby if the destination
register is also a source for the multiplication it will be
clobbered. This doesn't break any assembly code in the std lib but
could affect future work.

To fix this I have gone through the floating point instructions and
removed all unnecessary 3-/4-operand emulation. The compiler doesn't
need it and assembly writers don't need it, it's just a source of
bugs.

I've also deleted the FNMADD family of emulated instructions. They
aren't used anywhere.

Change-Id: Ic07cedcf141a6a3b43a0c84895460f6cfbf56c04
Reviewed-on: https://go-review.googlesource.com/33350
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-02-10 16:11:25 +00:00
Alberto Donizetti f44e587031 math: check overflow in amd64 Exp implementation
Unlike the pure go implementation used by every other architecture,
the amd64 asm implementation of Exp does not fail early if the
argument is known to overflow. Make it fail early.

Cost of the check is < 1ns (on an old Sandy Bridge machine):

name   old time/op  new time/op  delta
Exp-4  18.3ns ± 1%  18.7ns ± 1%  +2.08%  (p=0.000 n=18+20)

Fixes #14932
Fixes #18912

Change-Id: I04b3f9b4ee853822cbdc97feade726fbe2907289
Reviewed-on: https://go-review.googlesource.com/36271
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-10 13:40:08 +00:00
Robert Griesemer 1f93ba66d6 math/big: add IsInt64/IsUint64 predicates
Change-Id: Ia5ed3919cb492009ac8f66d175b47a69f83ee4f1
Reviewed-on: https://go-review.googlesource.com/36487
Reviewed-by: Alan Donovan <adonovan@google.com>
2017-02-07 23:02:33 +00:00
Russ Cox 850e55b8c0 crypto/*: document use or non-use of constant-time algorithms
Fixes #16821.

Change-Id: I63d5f3d7cfba1c76259912d754025c5f3cbe4a56
Reviewed-on: https://go-review.googlesource.com/31573
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-12-07 16:34:50 +00:00
Russ Cox 3f69822a9a math/rand: export Source64, mainly for documentation value
There is some code value too: types intending to implement
Source64 can write a conversion confirming that.

For #4254 and the Go 1.8 release notes.

Change-Id: I7fc350a84f3a963e4dab317ad228fa340dda5c66
Reviewed-on: https://go-review.googlesource.com/33456
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-23 04:29:25 +00:00
Russ Cox 37d078ede3 math/big: add Baillie-PSW test to (*Int).ProbablyPrime
After x.ProbablyPrime(n) passes the n Miller-Rabin rounds,
add a Baillie-PSW test before declaring x probably prime.

Although the provable error bounds are unchanged, the empirical
error bounds drop dramatically: there are no known inputs
for which Baillie-PSW gives the wrong answer. For example,
before this CL, big.NewInt(443*1327).ProbablyPrime(1) == true.
Now it is (correctly) false.

The new Baillie-PSW test is two pieces: an added Miller-Rabin
round with base 2, and a so-called extra strong Lucas test.
(See the references listed in prime.go for more details.)
The Lucas test takes about 3.5x as long as the Miller-Rabin round,
which is close to theoretical expectations.

name                              time/op
ProbablyPrime/Lucas             2.91ms ± 2%
ProbablyPrime/MillerRabinBase2   850µs ± 1%
ProbablyPrime/n=0               3.75ms ± 3%

The speed of prime testing for a prime input does get slower:

name                  old time/op  new time/op   delta
ProbablyPrime/n=1    849µs ± 1%   4521µs ± 1%  +432.31%   (p=0.000 n=10+9)
ProbablyPrime/n=5   4.31ms ± 3%   7.87ms ± 1%   +82.70%  (p=0.000 n=10+10)
ProbablyPrime/n=10  8.52ms ± 3%  12.28ms ± 1%   +44.11%  (p=0.000 n=10+10)
ProbablyPrime/n=20  16.9ms ± 2%   21.4ms ± 2%   +26.35%   (p=0.000 n=9+10)

However, because the Baillie-PSW test is only added when the old
ProbablyPrime(n) would return true, testing composites runs at
the same speed as before, except in the case where the result
would have been incorrect and is now correct.

In particular, the most important use of this code is for
generating random primes in crypto/rand. That use spends
essentially all its time testing composites, so it is not
slowed down by the new Baillie-PSW check:

name                  old time/op  new time/op   delta
Prime                104ms ±22%    111ms ±16%      ~     (p=0.165 n=10+10)

Thanks to Serhat Şevki Dinçer for CL 20170, which this CL builds on.

Fixes #13229.

Change-Id: Id26dde9b012c7637c85f2e96355d029b6382812a
Reviewed-on: https://go-review.googlesource.com/30770
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-11-22 02:05:47 +00:00
Brad Fitzpatrick d8b14c5243 math/rand: make floating point tests shorter on mips and mipsle
Like GOARM=5 does.

Fixes #17944

Change-Id: Ica2a54a90fbd4a29471d1c6009ace2fcc5e82a73
Reviewed-on: https://go-review.googlesource.com/33326
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-11-16 19:22:53 +00:00
Dmitri Shuralyov d8264de868 all: spell "marshal" and "unmarshal" consistently
The tree is inconsistent about single l vs double l in those
words in documentation, test messages, and one error value text.

	$ git grep -E '[Mm]arshall(|s|er|ers|ed|ing)' | wc -l
	      42
	$ git grep -E '[Mm]arshal(|s|er|ers|ed|ing)' | wc -l
	    1694

Make it consistently a single l, per earlier decisions. This means
contributors won't be confused by misleading precedence, and it helps
consistency.

Change the spelling in one error value text in newRawAttributes of
crypto/x509 package to be consistent.

This change was generated with:

	perl -i -npe 's,([Mm]arshal)l(|s|er|ers|ed|ing),$1$2,' $(git grep -l -E '[Mm]arshall' | grep -v AUTHORS | grep -v CONTRIBUTORS)

Updates #12431.
Follows https://golang.org/cl/14150.

Change-Id: I85d28a2d7692862ccb02d6a09f5d18538b6049a2
Reviewed-on: https://go-review.googlesource.com/33017
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-12 00:13:35 +00:00
Bill O'Farrell b6a15683f0 math: use SIMD to accelerate some scalar math functions on s390x
Note, most math functions are structured to use stubs, so that they can
be accelerated with assembly on any platform.
Sinh, cosh, and tanh were not structued with stubs, so this CL does
that. This set of routines was chosen as likely to produce good speedups
with assembly on any platform.

Technique used was minimax polynomial approximation using tables of
polynomial coefficients, with argument range reduction.
A table of scaling factors was also used for cosh and log10.

                     before       after      speedup
BenchmarkCos         22.1 ns/op   6.79 ns/op  3.25x
BenchmarkCosh       125   ns/op  11.7  ns/op 10.68x
BenchmarkLog10       48.4 ns/op  12.5  ns/op  3.87x
BenchmarkSin         22.2 ns/op   6.55 ns/op  3.39x
BenchmarkSinh       125   ns/op  14.2  ns/op  8.80x
BenchmarkTanh        65.0 ns/op  15.1  ns/op  4.30x

Accuracy was tested against a high precision
reference function to determine maximum error.
Approximately 4,000,000 points were tested for each function,
producing the following result.
Note: ulperr is error in "units in the last place"

       max
      ulperr
sin    1.43 (returns NaN beyond +-2^50)
cos    1.79 (returns NaN beyond +-2^50)
cosh   1.05
sinh   3.02
tanh   3.69
log10  1.75

Also includes a set of tests to test non-vector functions even
when SIMD is enabled

Change-Id: Icb45f14d00864ee19ed973d209c3af21e4df4edc
Reviewed-on: https://go-review.googlesource.com/32352
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
2016-11-11 20:20:23 +00:00
Vladimir Stefanovic d1e9104fb2 math, math/big: add support for GOARCH=mips{,le}
Change-Id: I54e100cced5b49674937fb87d1e0f585f962aeb7
Reviewed-on: https://go-review.googlesource.com/31484
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-11-03 22:55:06 +00:00
Cherry Zhang 0dabbcdc43 math/big: flip long/short flag on TestFloat32Distribution
It looks like a typo in CL 30707.

Change-Id: Ia2d013567dbd1a49901d9be0cd2d5a103e6e38cf
Reviewed-on: https://go-review.googlesource.com/32187
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2016-10-27 21:44:37 +00:00
Bill O'Farrell 1e6b12a201 math/big: uses SIMD for some math big functions on s390x
The following benchmarks are improved by the amounts shown
(Others unaffected beyond the level of noise.)
Also adds a test to confirm non-SIMD implementation still correct,
even when run on SIMD-capable machine

Benchmark                   old            new
BenchmarkAddVV/100-18    66148.08 MB/s 117546.19 MB/s 1.8x
BenchmarkAddVV/1000-18   70168.27 MB/s 133478.96 MB/s 1.9x
BenchmarkAddVV/10000-18  67489.80 MB/s 100010.79 MB/s 1.5x
BenchmarkAddVV/100000-18 54329.99 MB/s  69232.45 MB/s 1.3x
BenchmarkAddVW/100-18     9929.10 MB/s  14841.31 MB/s 1.5x
BenchmarkAddVW/1000-18   10583.31 MB/s  18674.44 MB/s 1.76x
BenchmarkAddVW/10000-18  10521.15 MB/s  17484.10 MB/s 1.66x
BenchmarkAddVW/100000-18 10616.56 MB/s  18084.27 MB/s 1.7x

Change-Id: Ic9234c41a43f6c5e9d0e9377de8b4deeefc428a7
Reviewed-on: https://go-review.googlesource.com/32211
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-26 23:52:10 +00:00
Mohit Agarwal 5a9549260d math/cmplx: prevent infinite loop in tanSeries
The condition to determine if any further iterations are needed is
evaluated to false in case it encounters a NaN. Instead, flip the
condition to keep looping until the factor is greater than the machine
roundoff error.

Updates #17577

Change-Id: I058abe73fcd49d3ae4e2f7b33020437cc8f290c3
Reviewed-on: https://go-review.googlesource.com/31952
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-25 18:32:22 +00:00
Alexander Döring 4c9c023346 math,math/cmplx: fix linter issues
Change-Id: If061f1f120573cb109d97fa40806e160603cd593
Reviewed-on: https://go-review.googlesource.com/31871
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-24 23:25:46 +00:00
Mohit Agarwal a6141ebd3f math/big: fix alignment in Float.Parse docs
Leading spaces in a couple of lines instead of tabs cause those to be
misaligned (as seen on <https://golang.org/pkg/math/big/#Float.Parse>):

<<<
	number   = [ sign ] [ prefix ] mantissa [ exponent ] | infinity .
	sign     = "+" | "-" .
     prefix   = "0" ( "x" | "X" | "b" | "B" ) .
	mantissa = digits | digits "." [ digits ] | "." digits .
	exponent = ( "E" | "e" | "p" ) [ sign ] digits .
	digits   = digit { digit } .
	digit    = "0" ... "9" | "a" ... "z" | "A" ... "Z" .
     infinity = [ sign ] ( "inf" | "Inf" ) .
>>>

Replace the leading spaces with tabs so that those align well.

Change-Id: Ibba6cd53f340001bbd929067dc587feb071dc3bd
Reviewed-on: https://go-review.googlesource.com/31830
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-24 17:59:42 +00:00
Josh Bleecher Snyder accf5cc386 all: minor vet fixes
Change-Id: I22f0f3e792052762499f632571155768b4052bc9
Reviewed-on: https://go-review.googlesource.com/31759
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-24 17:27:37 +00:00
Emmanuel Odeke f36e1adaa2 math/big: implement Float.Scan, type assert fmt interfaces to enforce docs
Implements Float.Scan which satisfies fmt.Scanner interface.
Also enforces docs' interface implementation claims with compile time
type assertions, that is:
+ Float always implements fmt.Formatter and fmt.Scanner
+ Int always implements fmt.Formatter and fmt.Scanner
+ Rat always implements fmt.Formatter
which will ensure that the API claims are strictly matched.

Also note that Float.Scan doesn't handle ±Inf.

Fixes #17391

Change-Id: I3d3dfbe7f602066975c7a7794fe25b4c645440ce
Reviewed-on: https://go-review.googlesource.com/30723
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-19 03:25:30 +00:00
Mohit Agarwal 7eed848a17 math: speed up Gamma(+Inf)
Add special case for Gamma(+∞) which speeds it up:

benchmark            old ns/op     new ns/op     delta
BenchmarkGamma-4     14.5          7.44          -48.69%

The documentation for math.Gamma already specifies it as a special
case:

        Gamma(+Inf) = +Inf

The original C code that has been used as the reference implementation
(as mentioned in the comments in gamma.go) also treats Gamma(+∞) as a
special case:

if( x == INFINITY )
        return(x);

Change-Id: Idac36e19192b440475aec0796faa2d2c7f8abe0b
Reviewed-on: https://go-review.googlesource.com/31370
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-18 22:12:03 +00:00
Alberto Donizetti f6cdfc7987 math/big: add benchmarks for big.Float String
In addition to the DecimalConversion benchmark, that exercises the
String method of the internal decimal type on a range of small shifts,
add a few benchmarks for the big.Float String method. They can be used
to obtain more realistic data on the real-world performance of
big.Float printing.

Change-Id: I7ada324e7603cb1ce7492ccaf3382db0096223ba
Reviewed-on: https://go-review.googlesource.com/31275
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-18 05:54:35 +00:00
Russ Cox 9ee21f90d2 math/big: add (*Int).Sqrt
This is needed for some of the more complex primality tests
(to filter out exact squares), and while the code is simple the
boundary conditions are not obvious, so it seems worth having
in the library.

Change-Id: Ica994a6b6c1e412a6f6d9c3cf823f9b653c6bcbd
Reviewed-on: https://go-review.googlesource.com/30706
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-17 20:30:19 +00:00
Robert Griesemer 92221fe8bc math/big: slightly faster float->decimal conversion
Inspired by Alberto Donizetti's observations in
https://go-review.googlesource.com/#/c/30099/.

name                 old time/op  new time/op  delta
DecimalConversion-8   138µs ± 1%   136µs ± 2%  -1.85%  (p=0.000 n=10+10)

10 runs each, measured on a Mac Mini, 2.3 GHz Intel Core i7.

Performance improvements varied between -1.25% to -4.4%; -1.85% is
about in the middle of the observed improvement. The generated code
is slightly shorter in the inner loops of the conversion code.

Change-Id: I10fb3b2843da527691c39ad5e5e5bd37ed63e2fa
Reviewed-on: https://go-review.googlesource.com/31250
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-10-17 19:33:33 +00:00
Russ Cox f444b48fe4 encoding/json: fix decoding of null into Unmarshaler, TextUnmarshaler
1. Define behavior for Unmarshal of JSON null into Unmarshaler and
TextUnmarshaler. Specifically, an Unmarshaler will be given the
literal null and can decide what to do (because otherwise
json.RawMessage is impossible to implement), and a TextUnmarshaler
will be skipped over (because there is no text to unmarshal), like
most other inappropriate types. Document this in Unmarshal, with a
reminder in UnmarshalJSON about handling null.

2. Test all this.

3. Fix the TextUnmarshaler case, which was returning an unmarshalling
error, to match the definition.

4. Fix the error that had been used for the TextUnmarshaler, since it
was claiming that there was a JSON string when in fact the problem was
NOT having a string.

5. Adjust time.Time and big.Int's UnmarshalJSON to ignore null, as is
conventional.

Fixes #9037.

Change-Id: If78350414eb8dda712867dc8f4ca35a9db041b0c
Reviewed-on: https://go-review.googlesource.com/30944
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-17 15:21:33 +00:00
Russ Cox 88562dc83e math/big: move ProbablyPrime into its own source file
A later CL will be adding more code here.
It will help to keep it separate from the other code.

Change-Id: I971ba53de819cd10991b51fdec665984939a5f9b
Reviewed-on: https://go-review.googlesource.com/30709
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-11 16:16:17 +00:00
Russ Cox 9927f25d71 math/big: test and optimize Exp(2, y, n) for large y, odd n
The Montgomery multiply code is applicable to this case
but was being bypassed. Don't do that.

The old test len(x) > 1 was really just a bad approximation to x > 1.

name    old time/op  new time/op  delta
Exp-8   5.56ms ± 4%  5.73ms ± 3%     ~     (p=0.095 n=5+5)
Exp2-8  7.59ms ± 1%  5.66ms ± 1%  -25.40%  (p=0.008 n=5+5)

This comes up especially when doing Fermat (Miller-Rabin)
primality tests with base 2.

Change-Id: I4cc02978db6dfa93f7f3c8f32718e25eedb4f5ed
Reviewed-on: https://go-review.googlesource.com/30708
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-11 16:15:51 +00:00
Russ Cox 9a8832f142 math/big: move exhaustive tests behind -long flag
This way you can still run 'go test' or 'go bench -run Foo'
without wondering why it is taking so very long.

Change-Id: Icfa097a6deb1d6682acb7be9f34729215c29eabb
Reviewed-on: https://go-review.googlesource.com/30707
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-10-11 16:15:12 +00:00
Russ Cox 3a9072829e math/big: make division faster
- Add new BenchmarkQuoRem.
- Eliminate allocation in divLarge nat pool
- Unroll mulAddVWW body 4x
- Remove some redundant slice loads in divLarge

name      old time/op  new time/op  delta
QuoRem-8  2.18µs ± 1%  1.93µs ± 1%  -11.38%  (p=0.000 n=19+18)

The starting point in the comparison here is Cherry's
pending CL to turn mulWW and divWW into intrinsics.
The optimizations in divLarge work best because all
the function calls are gone. The effect of this CL is not
as large if you don't assume Cherry's CL.

Change-Id: Ia6138907489c5b9168497912e43705634e163b35
Reviewed-on: https://go-review.googlesource.com/30613
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-10-10 18:50:23 +00:00
Robert Griesemer 95a6572b2b math/big: Rat.SetString to report error if input is not consumed entirely
Also, document behavior explicitly for all SetString implementations.

Fixes #17001.

Change-Id: Iccc882b4bc7f8b61b6092f330e405c146a80dc98
Reviewed-on: https://go-review.googlesource.com/30472
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-10-06 20:37:01 +00:00
Alexander Döring 7b4a224667 math/cmplx: add examples for Abs, Exp, Polar
Updates #16360

Change-Id: I941519981ff5bda3a113e14fa6be718eb4d2bf83
Reviewed-on: https://go-review.googlesource.com/30554
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-06 19:49:12 +00:00
Russ Cox 4f3a641e6e math: fix Gamma(-171.5) on all platforms
Using 387 mode was computing it without underflow to zero,
apparently due to an 80-bit intermediate. Avoid underflow even
with 64-bit floats.

This eliminates the TODOs in the test suite.

Fixes linux-386-387 build and fixes #11441.

Change-Id: I8abaa63bfdf040438a95625d1cb61042f0302473
Reviewed-on: https://go-review.googlesource.com/30540
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-06 14:53:09 +00:00
Russ Cox a39920fdbb math: fix Gamma(x) for x < -170.5 and other corner cases
Fixes #11441.

Test tables generated by

	package main

	import (
		"bytes"
		"fmt"
		"log"
		"os/exec"
		"strconv"
		"strings"
	)

	var inputs = []float64{
		0.5,
		1.5,
		2.5,
		3.5,
		-0.5,
		-1.5,
		-2.5,
		-3.5,
		0.1,
		0.01,
		1e-8,
		1e-16,
		1e-3,
		1e-16,
		1e-308,
		5.6e-309,
		5.5e-309,
		1e-309,
		1e-323,
		5e-324,
		-0.1,
		-0.01,
		-1e-8,
		-1e-16,
		-1e-3,
		-1e-16,
		-1e-308,
		-5.6e-309,
		-5.5e-309,
		-1e-300 / 1e9,
		-1e-300 / 1e23,
		-5e-300 / 1e24,
		-0.9999999999999999,
		-1.0000000000000002,
		-1.9999999999999998,
		-2.0000000000000004,
		-100.00000000000001,
		-99.999999999999986,
		17,
		171,
		171.6,
		171.624,
		171.625,
		172,
		2000,
		-100.5,
		-160.5,
		-170.5,
		-171.5,
		-176.5,
		-177.5,
		-178.5,
		-179.5,
		-201.0001,
		-202.9999,
		-1000.5,
		-1000000000.3,
		-4503599627370495.5,
		-63.349078729022985,
		-127.45117632943295,
	}

	func main() {
		var buf bytes.Buffer
		for _, v := range inputs {
			fmt.Fprintf(&buf, "gamma(%.1000g)\n", v)
		}
		cmd := exec.Command("gp", "-q")
		cmd.Stdin = &buf
		out, err := cmd.CombinedOutput()
		if err != nil {
			log.Fatalf("gp: %v", err)
		}
		f := strings.Split(string(out), "\n")
		if len(f) > 0 && f[len(f)-1] == "" {
			f = f[:len(f)-1]
		}
		if len(f) != len(inputs) {
			log.Fatalf("gp: wrong output count\n%s\n", out)
		}
		for i, g := range f {
			gf, err := strconv.ParseFloat(strings.Replace(g, " E", "e", -1), 64)
			if err != nil {
				if strings.Contains(err.Error(), "value out of range") {
					if strings.HasPrefix(g, "-") {
						fmt.Printf("\t{%g, Inf(-1)},\n", inputs[i])
					} else {
						fmt.Printf("\t{%g, Inf(1)},\n", inputs[i])
					}
					continue
				}
				log.Fatal(err)
			}
			if gf == 0 && strings.HasPrefix(g, "-") {
				fmt.Printf("\t{%g, Copysign(0, -1)},\n", inputs[i])
				continue
			}
			fmt.Printf("\t{%g, %g},\n", inputs[i], gf)
		}
	}

Change-Id: Ie98c7751d92b8ffb40e8313f5ea10df0890e2feb
Reviewed-on: https://go-review.googlesource.com/30146
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
2016-10-05 03:53:13 +00:00
Russ Cox aab849e429 math: use portable Exp instead of 387 instructions on 386
The 387 implementation is less accurate and slower.

name     old time/op  new time/op  delta
Exp-8    29.7ns ± 2%  24.0ns ± 2%  -19.08%  (p=0.000 n=10+10)

This makes Gamma more accurate too.

Change-Id: Iad33b9cce0b087ccbce3e08ba7a6d285c4999d02
Reviewed-on: https://go-review.googlesource.com/30230
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-05 03:53:11 +00:00
Florian Uekermann 003a598bf2 math/rand: add Rand.Uint64
This adds Uint64 methods to Rand and rngSource.
Rand.Uint64 uses Source.Uint64 directly if it is present.

rngSource.Uint64 provides access to all 64 bits generated by the
underlying ALFG. To ensure high seed quality a 64th bit has been added
to all elements of the array of "cooked" random numbers that are used
for seeding. gen_cooked.go generates both the 63 bit and 64 bit array.

Fixes #4254

Change-Id: I22855618ac69abae3d2799b3e7e59996d4c5a4b1
Reviewed-on: https://go-review.googlesource.com/27253
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-03 15:04:39 +00:00
Ilya Tocar 731b3ed18d math: make sqrt smaller on AMD64
This makes function fit in 16 bytes, saving 16 bytes.

Change-Id: Iac5d2add42f6dae985b2a5cbe19ad4bd4bcc92ec
Reviewed-on: https://go-review.googlesource.com/29151
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-29 15:56:52 +00:00
Cherry Zhang ba94dd3438 math: add some assembly implementations on ARM64
Also add GP<->FP move addressing mode to FMOVS, FMOVD
instructions.

Ceil-8                 37.1ns ± 0%   7.9ns ± 0%  -78.64%          (p=0.000 n=4+5)
Dim-8                  20.9ns ± 1%  11.3ns ± 0%  -45.93%          (p=0.008 n=5+5)
Floor-8                22.9ns ± 0%   7.9ns ± 0%  -65.41%          (p=0.029 n=4+4)
Gamma-8                 117ns ± 0%    94ns ± 1%  -19.50%          (p=0.016 n=4+5)
PowInt-8                121ns ± 0%   108ns ± 1%  -11.07%          (p=0.008 n=5+5)
PowFrac-8               331ns ± 0%   318ns ± 0%   -3.93%          (p=0.000 n=5+4)
Trunc-8                18.8ns ± 0%   7.9ns ± 0%  -57.83%          (p=0.016 n=4+5)

Change-Id: I709b7f1a914b28adc27414522db551e2630cfb92
Reviewed-on: https://go-review.googlesource.com/29734
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-27 23:52:12 +00:00
Michal Bohuslávek 9ed0715bb6 math/big: support negative numbers in ModInverse
Fixes #16984

Change-Id: I3a330e82941a068ca6097985af4ab221275fd336
Reviewed-on: https://go-review.googlesource.com/29299
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
2016-09-27 00:42:56 +00:00
Alberto Donizetti 6bcd258095 math/big: better SetFloat64 example in doc
Fixes #17221

Change-Id: Idaa2af6b8646651ea72195671d1a4b5c370a5a22
Reviewed-on: https://go-review.googlesource.com/29711
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-09-26 18:30:35 +00:00
Lynn Boger 3311275ce8 math, cmd/internal/obj/ppc64: improve floor, ceil, trunc with asm
This adds the instructions frim, frip, and friz to the ppc64x
assembler for use in implementing the math.Floor, math.Ceil, and
math.Trunc functions to improve performance.

Fixes #17185

BenchmarkCeil-128                    21.4          6.99          -67.34%
BenchmarkFloor-128                   13.9          6.37          -54.17%
BenchmarkTrunc-128                   12.7          6.33          -50.16%

Change-Id: I96131bd4e8c9c8dbafb25bfeb544cf9d2dbb4282
Reviewed-on: https://go-review.googlesource.com/29654
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
2016-09-23 13:03:08 +00:00
Michael Munday e94c52933b cmd/compile: intrinsify Ctz{32,64} and Bswap{32,64} on s390x
Also adds the 'find leftmost one' instruction (FLOGR) and replaces the
WORD-encoded use of FLOGR in math/big with it.

Change-Id: I18e7cd19e75b8501a6ae8bd925471f7e37ded206
Reviewed-on: https://go-review.googlesource.com/29372
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-19 19:03:01 +00:00
Brad Fitzpatrick 6f135bfd92 math/big: cut 2 minutes off race tests
No need to test so many sizes in race mode, especially for a package
which doesn't use goroutines.

Reduces test time from 2.5 minutes to 25 seconds.

Updates #17104

Change-Id: I7065b39273f82edece385c0d67b3f2d83d4934b8
Reviewed-on: https://go-review.googlesource.com/29163
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-09-14 19:11:43 +00:00
Michael Munday f1515a01fd runtime, math/big: allow R0 on s390x to contain values other than 0
The new SSA backend for s390x can use R0 as a general purpose register.
This change modifies assembly code to either avoid using R0 entirely
or explicitly set R0 to 0.

R0 can still be safely used as 0 in address calculations.

Change-Id: I3efa723e9ef322a91a408bd8c31768d7858526c8
Reviewed-on: https://go-review.googlesource.com/28976
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-12 18:06:01 +00:00
Ilya Tocar 6e703ae709 math: fix sqrt regression on AMD64
1.7 introduced a significant regression compared to 1.6:

SqrtIndirect-4  2.32ns ± 0%  7.86ns ± 0%  +238.79%        (p=0.000 n=20+18)

This is caused by sqrtsd preserving upper part of destination register.
Which introduces dependency on previous  value of X0.
In 1.6 benchmark loop didn't use X0 immediately after call:

callq  *%rbx
movsd  0x8(%rsp),%xmm2
movsd  0x20(%rsp),%xmm1
addsd  %xmm2,%xmm1
mov    0x18(%rsp),%rax
inc    %rax
jmp    loop

In 1.7 however xmm0 is used just after call:

callq  *%rbx
mov    0x10(%rsp),%rcx
lea    0x1(%rcx),%rax
movsd  0x8(%rsp),%xmm0
movsd  0x18(%rsp),%xmm1

I've  verified that this is caused by dependency, by inserting
XORPS X0,X0 in the beginning of math.Sqrt, which puts performance back on 1.6 level.

Splitting SQRTSD mem,reg into:
MOVSD mem,reg
SQRTSD reg,reg

Removes dependency, because MOVSD (load version)
doesn't need to preserve upper part of a register.
And reg,reg operation is solved by renamer in CPU.

As a result of this change regression is gone:
SqrtIndirect-4  7.86ns ± 0%  2.33ns ± 0%  -70.36%  (p=0.000 n=18+17)

This also removes old Sqrt benchmarks, in favor of benchmarks measuring latency.
Only SqrtIndirect is kept, to show impact of this patch.

Change-Id: Ic7eebe8866445adff5bc38192fa8d64c9a6b8872
Reviewed-on: https://go-review.googlesource.com/28392
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-06 15:45:02 +00:00
David Glasser 82bc0d4e80 math/rand: document that NewSource sources race
While it was previously explicitly documented that "the default Source"
is safe for concurrent use, a careless reader can interpret that as
meaning "the implementation of the Source interface created by functions
in this package" rather than "the default shared Source used by
top-level functions". Be explicit that the Source returned by NewSource
is not safe for use by multiple goroutines.

Fixes #3611.

Change-Id: Iae4bc04c3887ad6e2491e36e38feda40324022c5
Reviewed-on: https://go-review.googlesource.com/25501
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-02 05:16:21 +00:00
Ilya Tocar 2a2cab2911 math: speed up bessel functions on AMD64
J0-4            71.9ns ± 1%  54.6ns ± 0%  -24.08%  (p=0.000 n=20+18)
J1-4            71.6ns ± 0%  55.4ns ± 0%  -22.60%  (p=0.000 n=19+20)
Jn-4             153ns ± 0%   118ns ± 1%  -22.71%  (p=0.000 n=20+20)
Y0-4            70.8ns ± 0%  53.9ns ± 0%  -23.87%  (p=0.000 n=19+19)
Y1-4            70.8ns ± 0%  54.1ns ± 0%  -23.54%  (p=0.000 n=20+20)
Yn-4             149ns ± 0%   116ns ± 0%  -22.15%  (p=0.000 n=19+20)

Fixes #16889

Change-Id: Ie88496407b42f6acb918ffae1226b1b4c0500cb9
Reviewed-on: https://go-review.googlesource.com/28086
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-08-31 14:45:29 +00:00
Ethan Miller 4955147291 math/big: add assembly implementation of arith for ppc64{le}
The existing implementation used a pure go implementation, leading to slow
cryptographic performance.

Implemented mulWW, subVV, mulAddVWW, addMulVVW, and bitLen for
ppc64{le}.
Implemented divWW for ppc64le only, as the DIVDEU instruction is only
available on Power8 or newer.

benchcmp output:

benchmark                         old ns/op     new ns/op     delta
BenchmarkSignP384                 28934360      10877330      -62.41%
BenchmarkRSA2048Decrypt           41261033      5139930       -87.54%
BenchmarkRSA2048Sign              45231300      7610985       -83.17%
Benchmark3PrimeRSA2048Decrypt     20487300      2481408       -87.89%

Fixes #16621

Change-Id: If8b68963bb49909bde832f2bda08a3791c4f5b7a
Reviewed-on: https://go-review.googlesource.com/26951
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
2016-08-29 21:03:21 +00:00
Michael Munday 9f7ea61674 math: optimize Ceil, Floor and Trunc on s390x
Use the FIDBR instruction to round floating-point numbers to integers.

name   old time/op  new time/op  delta
Ceil   14.1ns ± 0%   3.0ns ± 0%  -78.89%  (p=0.000 n=10+10)
Floor  6.42ns ± 0%  3.03ns ± 0%  -52.80%  (p=0.000 n=10+10)
Trunc  6.67ns ± 0%  3.03ns ± 0%  -54.57%   (p=0.000 n=10+9)

Change-Id: I3b416f6d0bccaaa9b547de86356471365862399c
Reviewed-on: https://go-review.googlesource.com/27827
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-26 17:27:13 +00:00
Josh Bleecher Snyder 71ab9fa312 all: fix assembly vet issues
Add missing function prototypes.
Fix function prototypes.
Use FP references instead of SP references.
Fix variable names.
Update comments.
Clean up whitespace. (Not for vet.)

All fairly minor fixes to make vet happy.

Updates #11041

Change-Id: Ifab2cdf235ff61cdc226ab1d84b8467b5ac9446c
Reviewed-on: https://go-review.googlesource.com/27713
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-25 18:52:31 +00:00
Alberto Donizetti cda633b39b math/big: avoid allocation in float.{Add, Sub} when there's no aliasing
name               old time/op    new time/op    delta
FloatAdd/10-4         116ns ± 1%      82ns ± 0%   -28.74%  (p=0.008 n=5+5)
FloatAdd/100-4        124ns ± 0%      86ns ± 1%   -30.34%  (p=0.016 n=4+5)
FloatAdd/1000-4       192ns ± 1%     123ns ± 0%   -35.94%  (p=0.008 n=5+5)
FloatAdd/10000-4      826ns ± 0%     438ns ± 0%   -46.99%  (p=0.000 n=4+5)
FloatAdd/100000-4    6.82µs ± 1%    3.36µs ± 0%   -50.74%  (p=0.008 n=5+5)
FloatSub/10-4         108ns ± 1%      77ns ± 1%   -29.06%  (p=0.008 n=5+5)
FloatSub/100-4        115ns ± 0%      79ns ± 0%   -31.48%  (p=0.029 n=4+4)
FloatSub/1000-4       168ns ± 0%      99ns ± 0%   -41.09%  (p=0.029 n=4+4)
FloatSub/10000-4      690ns ± 2%     288ns ± 1%   -58.24%  (p=0.008 n=5+5)
FloatSub/100000-4    5.37µs ± 1%    2.10µs ± 1%   -60.89%  (p=0.008 n=5+5)

name               old alloc/op   new alloc/op   delta
FloatAdd/10-4         48.0B ± 0%     0.0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatAdd/100-4        64.0B ± 0%     0.0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatAdd/1000-4        176B ± 0%       0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatAdd/10000-4     1.41kB ± 0%   0.00kB ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatAdd/100000-4    13.6kB ± 0%    0.0kB ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatSub/10-4         48.0B ± 0%     0.0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatSub/100-4        64.0B ± 0%     0.0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatSub/1000-4        176B ± 0%       0B ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatSub/10000-4     1.41kB ± 0%   0.00kB ±NaN%  -100.00%  (p=0.008 n=5+5)
FloatSub/100000-4    13.6kB ± 0%    0.0kB ±NaN%  -100.00%  (p=0.008 n=5+5)

Fixes #14868

Change-Id: Ia2b8b1a8ef0868288ecb25f812b17bd03ff40d1c
Reviewed-on: https://go-review.googlesource.com/23568
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-08-17 17:56:42 +00:00
Florian Uekermann 507144c011 math/rand: Document origin of cooked pseudo-random numbers
The Source provided by math/rand relies on an array of cooked
pseudo-random 63bit integers for seeding. The origin of these
numbers is undocumented.

Add a standalone program in math/rand folder that generates
the 63bit integer array as well as a 64bit version supporting
extension of the Source to 64bit pseudo-random number
generation while maintaining the current sequence in the
lower 63bit.

The code is largely based on the initial implementation of the
random number generator in the go repository by Ken Thompson
(revision 399).

Change-Id: Ib4192aea8127595027116a0f5a7be53f11dc110b
Reviewed-on: https://go-review.googlesource.com/22230
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-17 14:50:18 +00:00
Josh Bleecher Snyder 302dd7b71e crypto/cipher, math/big: fix example names
Fixes (legit) vet warnings.
Fix some verb tenses while we're here.

Updates #11041

Change-Id: I27e995f55b38f4cf584e97a67b8545e8247e83d6
Reviewed-on: https://go-review.googlesource.com/27122
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-16 14:36:32 +00:00
Josh Bleecher Snyder 40cf4ad0ef all: fix "result not used" vet warnings
For tests, assign to _.
For benchmarks, assign to a sink.

Updates #11041

Change-Id: I87c5543245c7bc74dceb38902f4551768dd37948
Reviewed-on: https://go-review.googlesource.com/27116
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-16 14:15:10 +00:00
Josh Bleecher Snyder 3357a02b74 math/big: use array instead of slice for deBruijn lookups
This allows the compiler to remove a bounds check.

math/big/nat.go:681: index bounds check elided
math/big/nat.go:683: index bounds check elided

Change-Id: Ieecb89ec5e988761b06764bd671672015cd58e9d
Reviewed-on: https://go-review.googlesource.com/26663
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-16 00:22:13 +00:00
Ian Lance Taylor fb3cf5c686 math/rand: fix raciness in Rand.Read
There are no synchronization points protecting the readVal and readPos
variables. This leads to a race when Read is called concurrently.
Fix this by adding methods to lockedSource, which is the case where
a race matters.

Fixes #16308.

Change-Id: Ic028909955700906b2d71e5c37c02da21b0f4ad9
Reviewed-on: https://go-review.googlesource.com/24852
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-07-11 15:11:44 +00:00
Dmitri Popov 8d966bad6e math/rand: fix io.Reader implementation
Do not throw away the rest of Int63 value used for
generation random bytes. Save it in Rand struct and
re-use during the next Read call.

Fixes #16124

Change-Id: Ic70bd80c3c3a6590e60ac615e8b3c2324589bea3
Reviewed-on: https://go-review.googlesource.com/24251
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-27 22:18:09 +00:00
Konstantin Shaposhnikov 33fa855e6c math/rand: fix comment about bits of seed used by the default Source
Fixes #15788

Change-Id: I5a1fd1e5992f1c16cf8d8437d742bf02e1653b9c
Reviewed-on: https://go-review.googlesource.com/23461
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-26 05:00:39 +00:00
Nathan VanBenschoten 5e43dc943a math/big: special-case a 0 mantissa during Rat parsing
Previously, a 0 mantissa was special-cased during big.Float
parsing, but not during big.Rat parsing. This meant that a value
like 0e9999999999 would parse successfully in big.Float.SetString,
but would hang in big.Rat.SetString. This discrepancy became an
issue in https://golang.org/src/go/constant/value.go?#L250,
where the big.Float would report an exponent of 0, so
big.Rat.SetString would be used and would subsequently hang.

A Go Playground example of this is https://play.golang.org/p/3fy28eUJuF

The solution is to special-case a zero mantissa during big.Rat
parsing as well, so that neither big.Rat nor big.Float will hang when
parsing a value with 0 mantissa but a large exponent.

This was discovered using go-fuzz on CockroachDB:
https://github.com/cockroachdb/go-fuzz/blob/master/examples/parser/main.go

Fixes #16176

Change-Id: I775558a8682adbeba1cc9d20ba10f8ed26259c56
Reviewed-on: https://go-review.googlesource.com/24430
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-24 20:51:06 +00:00
Alberto Donizetti 5db44c17a2 math/big: avoid panic in float.Text with negative prec
Fixes #15918

Change-Id: I4b434aed262960a2e6c659d4c2296fbf662c3a52
Reviewed-on: https://go-review.googlesource.com/23633
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-01 19:20:52 +00:00
Marcel van Lohuizen 2deb9209de math/big: using Run for some more benchmarks
Change-Id: I3ede8098f405de5d88e51c8370d3b68446d40744
Reviewed-on: https://go-review.googlesource.com/23428
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-05-26 19:14:13 +00:00
Robert Griesemer 2168f2a68b math/big: simplify benchmarking code some more
Follow-up cleanup to https://golang.org/cl/23424/ .

Change-Id: Ifb05c1ff5327df6bc5f4cbc554e18363293f7960
Reviewed-on: https://go-review.googlesource.com/23446
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
2016-05-26 16:27:24 +00:00
Marcel van Lohuizen 07f0c19a30 math/big: use run for benchmarks
shortens code and gives an example of the use of Run.

Change-Id: I75ffaf762218a589274b4b62e19022e31e805d1b
Reviewed-on: https://go-review.googlesource.com/23424
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-25 17:49:37 +00:00
Jeff R. Allen 3474610fbc math/rand: Doc fix for how many bits Seed uses
Document the fact that the default Source uses only
the bottom 31 bits of the given seed.

Fixes #15788

Change-Id: If20d1ec44a55c793a4a0a388f84b9392c2102bd1
Reviewed-on: https://go-review.googlesource.com/23352
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-24 19:07:46 +00:00
Russ Cox ab4414773e math/big: write t*10 to multiply t by 10
The compiler has caught up.
In fact the compiler is ahead; it knows about a magic multiply-by-5 instruction:

	// compute '0' + byte(r - t*10) in AX
	MOVQ	t, AX
	LEAQ	(AX)(AX*4), AX
	SHLQ	$1, AX
	MOVQ	r, CX
	SUBQ	AX, CX
	LEAL	48(CX), AX

For comparison, the shifty version compiles to:

	// compute '0' + byte(r - t*10) in AX
	MOVQ	t, AX
	MOVQ	AX, CX
	SHLQ	$3, AX
	MOVQ	r, DX
	SUBQ	AX, DX
	SUBQ	CX, DX
	SUBQ	CX, DX
	LEAL	48(DX), AX

Fixes #2671.

Change-Id: Ifbf23dbfeb19c0bb020fa44eb2f025943969fb6b
Reviewed-on: https://go-review.googlesource.com/23372
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-24 13:34:20 +00:00
Emmanuel Odeke 53fd522c0d all: make copyright headers consistent with one space after period
Follows suit with https://go-review.googlesource.com/#/c/20111.

Generated by running
$ grep -R 'Go Authors.  All' * | cut -d":" -f1 | while read F;do perl -pi -e 's/Go
Authors.  All/Go Authors. All/g' $F;done

The code in cmd/internal/unvendor wasn't changed.

Fixes #15213

Change-Id: I4f235cee0a62ec435f9e8540a1ec08ae03b1a75f
Reviewed-on: https://go-review.googlesource.com/21819
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-02 13:43:18 +00:00
Robert Griesemer aea224386e math/big: more tests, documentation for Flot gob marshalling
Follow-up to https://golang.org/cl/21755.
This turned out to be a bit more than just a few nits
as originally expected in that CL.

1) The actual mantissa may be shorter than required for the
   given precision (because of trailing 0's): no need to
   allocate space for it (and transmit 0's). This can save
   a lot of space when the precision is high: E.g., for
   prec == 1000, 16 words or 128 bytes are required at the
   most, but if the actual number is short, it may be much
   less (for the test cases present, it's significantly less).

2) The actual mantissa may be longer than the number of
   words required for the given precision: make sure to
   not overflow when encoding in bytes.

3) Add more documentation.

4) Add more tests.

Change-Id: I9f40c408cfdd9183a8e81076d2f7d6c75e7a00e9
Reviewed-on: https://go-review.googlesource.com/22324
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-04-20 21:16:21 +00:00
OneOfOne d8c9dd6048 math/big: implement GobDecode/Encode for big.Float
Added GobEncode/Decode and a test for them.

Fixes #14593

Change-Id: Ic8d3efd24d0313a1a66f01da293c4c1fd39764a8
Reviewed-on: https://go-review.googlesource.com/21755
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-04-20 17:51:01 +00:00
Matthew Dempsky 0da4dbe232 all: remove unnecessary type conversions
cmd and runtime were handled separately, and I'm intentionally skipped
syscall. This is the rest of the standard library.

CL generated mechanically with github.com/mdempsky/unconvert.

Change-Id: I9e0eff886974dedc37adb93f602064b83e469122
Reviewed-on: https://go-review.googlesource.com/22104
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-15 07:31:45 +00:00
Aliaksandr Valialkin 187afdebef math/big: re-use memory in Int.GCD
This improves TLS handshake performance.

benchmark                                 old ns/op     new ns/op     delta
BenchmarkGCD10x10/WithoutXY-4             965           968           +0.31%
BenchmarkGCD10x10/WithXY-4                1813          1391          -23.28%
BenchmarkGCD10x100/WithoutXY-4            1093          1075          -1.65%
BenchmarkGCD10x100/WithXY-4               2348          1676          -28.62%
BenchmarkGCD10x1000/WithoutXY-4           1569          1565          -0.25%
BenchmarkGCD10x1000/WithXY-4              4262          3242          -23.93%
BenchmarkGCD10x10000/WithoutXY-4          6069          6066          -0.05%
BenchmarkGCD10x10000/WithXY-4             12123         11331         -6.53%
BenchmarkGCD10x100000/WithoutXY-4         52664         52610         -0.10%
BenchmarkGCD10x100000/WithXY-4            97494         95649         -1.89%
BenchmarkGCD100x100/WithoutXY-4           5244          5228          -0.31%
BenchmarkGCD100x100/WithXY-4              22572         18630         -17.46%
BenchmarkGCD100x1000/WithoutXY-4          6143          6233          +1.47%
BenchmarkGCD100x1000/WithXY-4             24652         19357         -21.48%
BenchmarkGCD100x10000/WithoutXY-4         15725         15804         +0.50%
BenchmarkGCD100x10000/WithXY-4            60552         55973         -7.56%
BenchmarkGCD100x100000/WithoutXY-4        107008        107853        +0.79%
BenchmarkGCD100x100000/WithXY-4           349597        340994        -2.46%
BenchmarkGCD1000x1000/WithoutXY-4         63785         64434         +1.02%
BenchmarkGCD1000x1000/WithXY-4            373186        334035        -10.49%
BenchmarkGCD1000x10000/WithoutXY-4        78038         78241         +0.26%
BenchmarkGCD1000x10000/WithXY-4           543692        507034        -6.74%
BenchmarkGCD1000x100000/WithoutXY-4       205607        207727        +1.03%
BenchmarkGCD1000x100000/WithXY-4          2488113       2415323       -2.93%
BenchmarkGCD10000x10000/WithoutXY-4       1731340       1714992       -0.94%
BenchmarkGCD10000x10000/WithXY-4          10601046      7111329       -32.92%
BenchmarkGCD10000x100000/WithoutXY-4      2239155       2212173       -1.21%
BenchmarkGCD10000x100000/WithXY-4         30097040      26538887      -11.82%
BenchmarkGCD100000x100000/WithoutXY-4     119845326     119863916     +0.02%
BenchmarkGCD100000x100000/WithXY-4        768006543     426795966     -44.43%

benchmark                                 old allocs     new allocs     delta
BenchmarkGCD10x10/WithoutXY-4             5              5              +0.00%
BenchmarkGCD10x10/WithXY-4                17             9              -47.06%
BenchmarkGCD10x100/WithoutXY-4            6              6              +0.00%
BenchmarkGCD10x100/WithXY-4               21             9              -57.14%
BenchmarkGCD10x1000/WithoutXY-4           6              6              +0.00%
BenchmarkGCD10x1000/WithXY-4              30             12             -60.00%
BenchmarkGCD10x10000/WithoutXY-4          6              6              +0.00%
BenchmarkGCD10x10000/WithXY-4             26             12             -53.85%
BenchmarkGCD10x100000/WithoutXY-4         6              6              +0.00%
BenchmarkGCD10x100000/WithXY-4            28             12             -57.14%
BenchmarkGCD100x100/WithoutXY-4           5              5              +0.00%
BenchmarkGCD100x100/WithXY-4              183            61             -66.67%
BenchmarkGCD100x1000/WithoutXY-4          8              8              +0.00%
BenchmarkGCD100x1000/WithXY-4             170            47             -72.35%
BenchmarkGCD100x10000/WithoutXY-4         8              8              +0.00%
BenchmarkGCD100x10000/WithXY-4            200            67             -66.50%
BenchmarkGCD100x100000/WithoutXY-4        8              8              +0.00%
BenchmarkGCD100x100000/WithXY-4           188            65             -65.43%
BenchmarkGCD1000x1000/WithoutXY-4         5              5              +0.00%
BenchmarkGCD1000x1000/WithXY-4            2435           1193           -51.01%
BenchmarkGCD1000x10000/WithoutXY-4        8              8              +0.00%
BenchmarkGCD1000x10000/WithXY-4           2211           1076           -51.33%
BenchmarkGCD1000x100000/WithoutXY-4       8              8              +0.00%
BenchmarkGCD1000x100000/WithXY-4          2271           1108           -51.21%
BenchmarkGCD10000x10000/WithoutXY-4       5              5              +0.00%
BenchmarkGCD10000x10000/WithXY-4          23183          11605          -49.94%
BenchmarkGCD10000x100000/WithoutXY-4      8              8              +0.00%
BenchmarkGCD10000x100000/WithXY-4         23421          11717          -49.97%
BenchmarkGCD100000x100000/WithoutXY-4     5              5              +0.00%
BenchmarkGCD100000x100000/WithXY-4        232976         116815         -49.86%

benchmark                                 old bytes      new bytes     delta
BenchmarkGCD10x10/WithoutXY-4             208            208           +0.00%
BenchmarkGCD10x10/WithXY-4                736            432           -41.30%
BenchmarkGCD10x100/WithoutXY-4            256            256           +0.00%
BenchmarkGCD10x100/WithXY-4               896            432           -51.79%
BenchmarkGCD10x1000/WithoutXY-4           368            368           +0.00%
BenchmarkGCD10x1000/WithXY-4              1856           1152          -37.93%
BenchmarkGCD10x10000/WithoutXY-4          1616           1616          +0.00%
BenchmarkGCD10x10000/WithXY-4             7920           7376          -6.87%
BenchmarkGCD10x100000/WithoutXY-4         13776          13776         +0.00%
BenchmarkGCD10x100000/WithXY-4            68800          68176         -0.91%
BenchmarkGCD100x100/WithoutXY-4           208            208           +0.00%
BenchmarkGCD100x100/WithXY-4              6960           2112          -69.66%
BenchmarkGCD100x1000/WithoutXY-4          544            560           +2.94%
BenchmarkGCD100x1000/WithXY-4             7280           2400          -67.03%
BenchmarkGCD100x10000/WithoutXY-4         2896           2912          +0.55%
BenchmarkGCD100x10000/WithXY-4            15280          10002         -34.54%
BenchmarkGCD100x100000/WithoutXY-4        27344          27365         +0.08%
BenchmarkGCD100x100000/WithXY-4           88288          83427         -5.51%
BenchmarkGCD1000x1000/WithoutXY-4         544            544           +0.00%
BenchmarkGCD1000x1000/WithXY-4            178288         40043         -77.54%
BenchmarkGCD1000x10000/WithoutXY-4        3344           3136          -6.22%
BenchmarkGCD1000x10000/WithXY-4           188720         54432         -71.16%
BenchmarkGCD1000x100000/WithoutXY-4       27792          27592         -0.72%
BenchmarkGCD1000x100000/WithXY-4          373872         239447        -35.95%
BenchmarkGCD10000x10000/WithoutXY-4       4288           4288          +0.00%
BenchmarkGCD10000x10000/WithXY-4          11935584       481875        -95.96%
BenchmarkGCD10000x100000/WithoutXY-4      31296          28834         -7.87%
BenchmarkGCD10000x100000/WithXY-4         13237088       1662620       -87.44%
BenchmarkGCD100000x100000/WithoutXY-4     40768          40768         +0.00%
BenchmarkGCD100000x100000/WithXY-4        1165518864     14256010      -98.78%

Change-Id: I652b3244bd074a03f3bc9a87c282330f9e5f1507
Reviewed-on: https://go-review.googlesource.com/21506
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-07 17:19:37 +00:00
Michael Munday 1e7c61d8c3 math/big: add s390x function implementations
Change-Id: I2aadc885d6330460e494c687757f07c5e006f3b0
Reviewed-on: https://go-review.googlesource.com/20937
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-07 16:15:27 +00:00
Michael Munday 0382a30dd6 math: add functions and stubs for s390x
Includes assembly implementations of Sqrt and Dim.

Change-Id: I57472e8d31e2ee74bcebf9f8e818f765eb9b8abf
Reviewed-on: https://go-review.googlesource.com/20936
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-06 23:35:56 +00:00
Robert Griesemer 7c86263be2 math/big: much simplified and faster Float rounding
Change-Id: Iab0add7aee51a8c72a81f51d980d22d2fd612f5c
Reviewed-on: https://go-review.googlesource.com/20817
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-03-22 17:07:34 +00:00
Robert Griesemer a14537816e math/big: fix rounding to smallest denormal for Float.Float32/64
Converting a big.Float value x to a float32/64 value did not correctly
round x up to the smallest denormal float32/64 if x was smaller than the
smallest denormal float32/64, but larger than 0.5 of a smallest denormal
float32/64.

Handle this case explicitly and simplify some code in the turn.

For #14651.

Change-Id: I025e24bf8f0e671581a7de0abf7c1cd7e6403a6c
Reviewed-on: https://go-review.googlesource.com/20816
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-03-21 20:24:06 +00:00
Robert Griesemer bea2008b83 math/cmplx: added clarifying comment
Fixes #14890.

Change-Id: Ie790276b0e2ef94c92db3a777042d750269f876a
Reviewed-on: https://go-review.googlesource.com/20953
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-03-21 16:18:38 +00:00
Dominik Honnef b2cf571040 all: delete dead test code
This deletes unused code and helpers from tests.

Change-Id: Ie31d46115f558ceb8da6efbf90c3c204e03b0d7e
Reviewed-on: https://go-review.googlesource.com/20927
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-21 07:10:08 +00:00
Matthew Dempsky e28a3929ef math/big: cleanup documentation for Format methods
'b' is a standard verb for floating point values. The runes like '+'
and '#' are called "flags" by package fmt's documentation. The flag
'-' controls left/right justification, not anything related to signs.

Change-Id: Ia9cf81b002df373f274ce635fe09b5bd0066aa1c
Reviewed-on: https://go-review.googlesource.com/20930
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-21 02:49:32 +00:00
Matthew Dempsky 95c6c5f36b math/big: fix comment typos
Change-Id: I34cdc9cb3d32e86ff3a57db0012326c39cd55670
Reviewed-on: https://go-review.googlesource.com/20718
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-03-15 20:41:15 +00:00
Lynn Boger b4b2ddb867 math: improve sqrt for ppc64le,ppc64
The existing implementation uses code written in Go to
implement Sqrt; this adds the assembler to use the sqrt
instruction for Power and makes the necessary changes to
allow it to be inlined.

The following tests showed this relative improvement:

benchmark                 delta
BenchmarkSqrt             -97.91%
BenchmarkSqrtIndirect     -96.65%
BenchmarkSqrtGo           -35.93%
BenchmarkSqrtPrime        -96.94%

Fixes #14349

Change-Id: I8074f4dc63486e756587564ceb320aca300bf5fa
Reviewed-on: https://go-review.googlesource.com/19515
Reviewed-by: Minux Ma <minux@golang.org>
2016-03-10 15:01:21 +00:00
Brady Catherman 9323de3da7 testing: implement 'Unordered Output' in Examples.
Adds a type of output to Examples that allows tests to have unordered
output. This is intended to help clarify when the output of a command
will produce a fixed return, but that return might not be in an constant
order.

Examples where this is useful would be documenting the rand.Perm()
call, or perhaps the (os.File).Readdir(), both of which can not guarantee
order, but can guarantee the elements of the output.

Fixes #10149

Change-Id: Iaf0cf1580b686afebd79718ed67ea744f5ed9fc5
Reviewed-on: https://go-review.googlesource.com/19280
Reviewed-by: Andrew Gerrand <adg@golang.org>
2016-03-09 04:34:41 +00:00
Robert Griesemer 3858efcc58 math/big: use correct precision in Float.Float32/64 for denormals
When a big.Float is converted to a denormal float32/64, the rounding
precision depends on the size of the denormal. Rounding may round up
and thus change the size (exponent) of the denormal. Recompute the
correct precision again for correct placement of the mantissa.

Fixes #14553.

Change-Id: Iedab5810a2d2a405cc5da28c6de7be34cb035b86
Reviewed-on: https://go-review.googlesource.com/20198
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-03-04 17:39:50 +00:00
Rob Pike 0f9cc465fa math: delete unused function sqrtC
It appears to be a trivial dreg. Unreferenced. Gone.

Change-Id: I4a5ceed48e84254bc8a07fdb04487a18a0edf965
Reviewed-on: https://go-review.googlesource.com/20122
Run-TryBot: Rob Pike <r@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
2016-03-03 02:29:09 +00:00
Brad Fitzpatrick 5fea2ccc77 all: single space after period.
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-02 00:13:47 +00:00
Brad Fitzpatrick 519474451a all: make copyright headers consistent with one space after period
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.

Go policy has been single space after periods in comments for some time.

The copyright header template at:

    https://golang.org/doc/contribute.html#copyright

also uses a single space.

Make them all consistent.

Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-01 23:34:33 +00:00
Martin Möhrmann fdd0179bb1 all: fix typos and spelling
Change-Id: Icd06d99c42b8299fd931c7da821e1f418684d913
Reviewed-on: https://go-review.googlesource.com/19829
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-02-24 18:42:29 +00:00
Nathan VanBenschoten b04f3b06ec all: replace strings.Index with strings.Contains where possible
Change-Id: Ia613f1c37bfce800ece0533a5326fca91d99a66a
Reviewed-on: https://go-review.googlesource.com/18120
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
2016-02-19 01:06:05 +00:00
Russ Cox 1e066cad1b math/big: fix Exp(x, x, x) for certain large x
Fixes #13907.

Change-Id: Ieaa5183f399b12a9177372212adf481c8f0b4a0d
Reviewed-on: https://go-review.googlesource.com/18491
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Vlad Krasnov <vlad@cloudflare.com>
Reviewed-by: Adam Langley <agl@golang.org>
2016-01-13 01:43:35 +00:00
Robert Griesemer 5e059d1c31 math/big: fix typo in comment
Fixes #13875.

Change-Id: Icbb85c858d0bc545499a2b31622e9e7abdd7e5f9
Reviewed-on: https://go-review.googlesource.com/18441
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-01-08 20:18:10 +00:00
Russ Cox 04d732b4c2 build: shorten a few packages with long tests
Takes 3% off my all.bash run time.

For #10571.

Change-Id: I8f00f523d6919e87182d35722a669b0b96b8218b
Reviewed-on: https://go-review.googlesource.com/18087
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-12-29 15:46:44 +00:00
Russ Cox 6bcec09ceb math/big: additional Montgomery cleanup
Also fix bug reported in CL 17510.

Found during fix of #13515 in CL 17672, but separate from the fix.

Change-Id: I4b1024569a98f5cfd2ebb442ec3d64356164d284
Reviewed-on: https://go-review.googlesource.com/17673
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-12-16 20:25:29 +00:00
Russ Cox 4306352182 math/big: fix carry propagation in Int.Exp Montgomery code
Fixes #13515.

Change-Id: I7dd5fbc816e5ea135f7d81f6735e7601f636fe4f
Reviewed-on: https://go-review.googlesource.com/17672
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-12-11 17:24:29 +00:00
David Chase 38255cbd1b math/rand: improve uniformity of rand.Float64,Float32
Replaced code that substituted 0 for rounded-up 1 with
code to try again.  This has minimal effect on the existing
stream of random numbers, but restores uniformity.

Fixes #12290.

Change-Id: Ib68f0b0a4a173339bcd0274cc16509f7b0977de8
Reviewed-on: https://go-review.googlesource.com/17670
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-12-11 15:17:42 +00:00
Russ Cox 0816432918 math/big: fix misuse of Unicode
ˆ (U+02C6) is a circumflex accent, not an exponentiation operator.
In the rest of the source code for this package, exponentation is
written as **, so do the same here.

Change-Id: I107b85be242ab79d152eb8a6fcf3ca2b197d7658
Reviewed-on: https://go-review.googlesource.com/17671
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-12-11 03:37:57 +00:00
Brad Fitzpatrick 7e1791b97f math/big: fix typo
Found by github user asukakenji.

Change-Id: I4c76316b69e8a243fb6bf280283f3722e728d853
Reviewed-on: https://go-review.googlesource.com/17641
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-12-09 16:59:52 +00:00
Jingguo Yao fb01ad21c2 math/rand: add a comment for the i=0 iteration
Fixes #13215

Change-Id: I126117d42e7c1e69cbc7fad0760e225b03ed15bd
Reviewed-on: https://go-review.googlesource.com/16852
Reviewed-by: Keith Randall <khr@golang.org>
2015-11-15 08:21:29 +00:00
Yao Zhang 4a25f6ca05 math, math/big: added support for mips64{,le}
Change-Id: I5129a5b9dbbc57d97da723c2fc247bd28f951817
Reviewed-on: https://go-review.googlesource.com/14451
Reviewed-by: Minux Ma <minux@golang.org>
2015-11-12 04:49:57 +00:00
Matthew Dempsky 7832c82bf5 math: fix bad shift in Expm1
Noticed by cmd/vet.

Expected values array produced by Python instead of Keisan because:

1) Keisan's website calculator is painfully difficult to copy/paste
values into and out of, and

2) after tediously computing e^(vf[i] * 10) - 1 via Keisan I
discovered that Keisan computing vf[i]*10 in a higher precision was
giving substantially different output values.

Also, testing uses "close" instead of "veryclose" because 386's
assembly implementation produces values for some of the test cases
that fail "veryclose".  Curiously, Expm1(vf[i]*10) is identical to
Exp(vf[i]*10)-1 on 386, whereas with the portable implementation
they're only "veryclose".

Investigating these questions is left to someone else.  I just wanted
to fix the cmd/vet warning.

Fixes #13101.

Change-Id: Ica8f6c267d01aa4cc31f53593e95812746942fbc
Reviewed-on: https://go-review.googlesource.com/16505
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Klaus Post <klauspost@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-10-30 22:55:19 +00:00
Brad Fitzpatrick a59a27564b math: fix typo and braino in my earlier commit
The bug number was a typo, and I forgot to switch the implementation
back to if statements after the change from Float64bits in the first
patchset back to branching.

if statements can currently be inlined, but switch cannot (#13071)

Change-Id: I81d0cf64bda69186c3d747a07047f6a694f8fa70
Reviewed-on: https://go-review.googlesource.com/16446
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-29 21:12:08 +00:00
Brad Fitzpatrick 6f8a66536b math: replace assembly implementations of Abs with pure Go version
The compiler can do a fine job, and can also inline it.

From Jeremy Jackins's observation and rsc's recommendation in thread:

"Pure Go math.Abs outperforms assembly version"
https://groups.google.com/forum/#!topic/golang-dev/nP5mWvwAXZo

Updates #13095

Change-Id: I3066f8eaa327bb403173b29791cc8661d7c0532c
Reviewed-on: https://go-review.googlesource.com/16444
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-29 19:44:59 +00:00
Caleb Spare 22d4c8bf13 math: fix normalization bug in pure-Go sqrt
Fixes #13013

Change-Id: I6cf500eacdce76e303fc1cd92dd1c80eef0986bc
Reviewed-on: https://go-review.googlesource.com/16158
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-23 18:29:10 +00:00
David Crawshaw e4feb18fc2 math/big: fix SetMantExp comment
Change-Id: If30cf9c94b58e18564db46c15c6f5cc14ec1a6fa
Reviewed-on: https://go-review.googlesource.com/16271
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-10-23 16:38:27 +00:00
Charlie Dorian 6fed2a68f7 math: Modf(-0) returns -0,-0
Fixes #12867

Change-Id: I8ba81c622bce2a77a6142f941603198582eaf8a4
Reviewed-on: https://go-review.googlesource.com/15570
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-10-09 17:09:16 +00:00
Charlie Dorian 1ef9b5a5b9 math/cmplx: make error tolerance test function of expected value
Copy math package CL 12230 to cmplx package.

Change-Id: I3345b782b84b5b98e2b6a60d8774c7e7cede2891
Reviewed-on: https://go-review.googlesource.com/15500
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-07 18:41:11 +00:00
Damian Gryski 2fd016422e math/big: check return value from quick.Check() for GCD tests
Change-Id: I46c12aaaf453365c157604dfb1486605cfefd7af
Reviewed-on: https://go-review.googlesource.com/15263
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-03 16:06:44 +00:00
Ilya Tocar 37cfb2e07e math: optimize ceil/floor functions on amd64
Use SSE 4.1 rounding instruction to perform rounding
Results (haswell):

name      old time/op  new time/op  delta
Floor-48  2.71ns ± 0%  1.87ns ± 1%  -31.17%  (p=0.000 n=16+19)
Ceil-48   3.09ns ± 3%  2.16ns ± 0%  -30.16%  (p=0.000 n=19+12)

Change-Id: If63715879eed6530b1eb4fc96132d827f8f43909
Reviewed-on: https://go-review.googlesource.com/14561
Reviewed-by: Klaus Post <klauspost@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2015-10-03 15:55:08 +00:00
Adam Langley 5d5889c4d9 math/big: correct documentation for ProbablyPrime.
As akalin points out in the bug, the comment previously claimed that the
probability that the input is prime given that the function returned
true is 1 - ¼ⁿ. But that's wrong: the correct statement is that the
probability of the function returning false given a composite input is
1 - ¼ⁿ.

This is not nearly as helpful, but at least it's truthful. A number of
other (correct) expressions are suggested on the bug, but I think that
the simplier one is preferable.

This change also notes that the function is not suitable for
adversarial inputs since it's deterministic.

Fixes #12274.

Change-Id: I6a0871d103b126ee5a5a922a8c6993055cb7b1ed
Reviewed-on: https://go-review.googlesource.com/14052
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-09-30 00:39:00 +00:00
Robert Griesemer 3b9e8bb7f2 math/big: more documentation
Good enough for now.

Fixes #11241.

Change-Id: Ieb50809f104d20bcbe14daecac503f72486bec92
Reviewed-on: https://go-review.googlesource.com/15111
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-29 00:23:51 +00:00
Robert Griesemer 18563f8ab4 math/big: clean up *Int encoding tests
- more uniform naming
- test sign more deliberately
- remove superfluous test (JSON encoder always uses the JSON marshaler if present)

Change-Id: I37b1e367c01fc8bae1e06adbdb72dd366c08d5ce
Reviewed-on: https://go-review.googlesource.com/15110
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-29 00:23:31 +00:00
Robert Griesemer 38c5fd5cf8 math/big: implement Float.Text(Un)Marshaler
Fixes #12256.

Change-Id: Ie4a3337996da5c060b27530b076048ffead85f3b
Reviewed-on: https://go-review.googlesource.com/15040
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-29 00:21:45 +00:00
Robert Griesemer 3d4cd144cc math/big: improved documentation
- moved existing package documentation from nat.go to doc.go
- expanded on it

For #11241.

Change-Id: Ie75a2b0178a8904a4154307a1f5080d7efc5489a
Reviewed-on: https://go-review.googlesource.com/15042
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-28 16:27:52 +00:00
Robert Griesemer 59129c6a93 math/big: remove some string conversions in Int encoding
Change-Id: I1180aa3d30fb8563c8e6ecefeb3296af0a88f5a6
Reviewed-on: https://go-review.googlesource.com/14998
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-25 22:25:52 +00:00
Robert Griesemer 7fa5a11ea1 math/big: move Int/Rat gob/json/xml functionality in separate files
Like int/rat/float conversions, move this functionality into separate
implementation and test files.

No implementation changes besides the move.

Change-Id: If19c45f5a72a57b95cbce2329724693ae5a4807d
Reviewed-on: https://go-review.googlesource.com/14997
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-25 22:25:36 +00:00
Robert Griesemer e937eeeccd math/big: removed more unnecessary string conversions
- renamed (nat) itoa to utoa (since that's what it is)
- added (nat) itoa that takes a sign parameter; this helps removing a few string copies
- used buffers instead of string+ in Rat conversions

Change-Id: I6b37a6b39557ae311cafdfe5c4a26e9246bde1a9
Reviewed-on: https://go-review.googlesource.com/14995
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-25 22:25:12 +00:00
Robert Griesemer 8d701f092d math/big: implement Int.Text, Int.Append
This makes the Int conversion routines match the respective strconv
and big.Float conversion routines.

Change-Id: I5cfcda1632ee52fe87c5bb75892bdda76cc3af15
Reviewed-on: https://go-review.googlesource.com/14994
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-25 22:24:49 +00:00
Robert Griesemer b07a9efa78 math/big: faster string conversion routines
Eliminated unnecessary string conversions throughout and removed
(internal) capability for arbitrary character sets in conversion
routines (functionality was not exported and not used internally).

benchmark                         old ns/op     new ns/op     delta
BenchmarkDecimalConversion-8      198283        187085        -5.65%
BenchmarkStringPiParallel-8       46116         47822         +3.70%
BenchmarkString10Base2-8          216           166           -23.15%
BenchmarkString100Base2-8         886           762           -14.00%
BenchmarkString1000Base2-8        7296          6625          -9.20%
BenchmarkString10000Base2-8       72371         65563         -9.41%
BenchmarkString100000Base2-8      725849        672766        -7.31%
BenchmarkString10Base8-8          160           114           -28.75%
BenchmarkString100Base8-8         398           309           -22.36%
BenchmarkString1000Base8-8        2650          2244          -15.32%
BenchmarkString10000Base8-8       24974         21745         -12.93%
BenchmarkString100000Base8-8      245457        217489        -11.39%
BenchmarkString10Base10-8         337           288           -14.54%
BenchmarkString100Base10-8        1298          1046          -19.41%
BenchmarkString1000Base10-8       6200          5752          -7.23%
BenchmarkString10000Base10-8      24942         22589         -9.43%
BenchmarkString100000Base10-8     8012921       7947152       -0.82%
BenchmarkString10Base16-8         156           107           -31.41%
BenchmarkString100Base16-8        344           255           -25.87%
BenchmarkString1000Base16-8       2067          1705          -17.51%
BenchmarkString10000Base16-8      19026         16112         -15.32%
BenchmarkString100000Base16-8     184038        163457        -11.18%

Change-Id: I68bd807529bd9b985f4b6ac2a87764bcc1a7d2f7
Reviewed-on: https://go-review.googlesource.com/14926
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-24 23:07:47 +00:00
Robert Griesemer 3f7c3e01db math/big: fix test for denormalized inputs and enable more test cases
Also: removed unnecessary BUG comment (was fixed).

Change-Id: I8f11fbcb4e30a19ec5a25df742b3e25e2ee7f846
Reviewed-on: https://go-review.googlesource.com/14923
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-24 22:23:55 +00:00
Robert Griesemer 59a6ba5634 math/big: factored out an internal accessor method (cleanup), added benchmark
Current result of DecimalConversion benchmark (for future reference):

BenchmarkDecimalConversion-8	   10000	    204770 ns/op

Measured on Mac Mini (late 2012) running OS X 10.10.5,
2.3 GHz Intel Core i7, 8 GB 1333 MHz DDR3.

Also: Removed comment suggesting to implement decimal by representing
digits as numbers 0..9 rather than ASCII chars '0'..'9' to avoid
repeated +/-'0' operations. Tried and it appears (per above benchmark)
that the +/-'0' operations are neglibile but the addition conversion
passes around it are not and that it makes things significantly slower.

Change-Id: I6ee033b1172043248093cc5d02abff5fc54c2e7a
Reviewed-on: https://go-review.googlesource.com/14857
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-23 20:25:59 +00:00
Robert Griesemer 4fc9565ffc math/big: implement negative precision for Float.Append/Text
Enabled all but a handful of disabled Float formatting test cases.

Fixes #10991.

Change-Id: Id18e160e857be2743429a377000e996978015a1a
Reviewed-on: https://go-review.googlesource.com/14850
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-23 16:45:38 +00:00
Robert Griesemer b5d94b7d41 math/big: add test cases for min/max exponent values
Change-Id: I2e74e39628285e2fecaab712be6cff230619a6c2
Reviewed-on: https://go-review.googlesource.com/14778
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-22 07:59:02 +00:00
Robert Griesemer 16b3675bc8 math/big: optimize Float.Parse by reducing powers of 10 to powers of 2 and 5
Instead of computing the final adjustment factor as a power of 10,
it's more efficient to split 10**e into 2**e * 5**e . Powers of 2
are trivially added to the Float exponent, and powers of 5 are
smaller and thus faster to compute.

Also, use a table of uint64 values rather than float64 values for
initial power value. uint64 values appear to be faster to convert
to Floats (useful for small exponents).

Added two small benchmarks to confirm that there's no regresssion.

benchmark                         old ns/op     new ns/op     delta
BenchmarkParseFloatSmallExp-8     17543         16220         -7.54%
BenchmarkParseFloatLargeExp-8     60865         59996         -1.43%

Change-Id: I3efd7556b023316f86f334137a67fe0c6d52f8ef
Reviewed-on: https://go-review.googlesource.com/14782
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-09-22 05:48:02 +00:00
Spencer Nelson f9e404c1c5 math/rand: make Rand fulfill the Reader interface
Add a Read function to Rand which reads random bytes into a buffer.

Fixes #8330

Change-Id: I85b90277b8be9287c6697def8dbefe0029b6ee06
Reviewed-on: https://go-review.googlesource.com/14522
Reviewed-by: Rob Pike <r@golang.org>
2015-09-16 17:54:01 +00:00
Alberto Donizetti 3d5bed2726 math/big: Add small complete example of big.Rat usage
Updates #11241

Change-Id: If71f651f3b8aca432c91314358b93f195217d9ec
Reviewed-on: https://go-review.googlesource.com/14317
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-09-15 17:46:22 +00:00
Rob Pike 67ddae87b9 all: use one 'l' when cancelling everywhere except Solaris
Fixes #11626.

Change-Id: I1b70c0844473c3b57a53d7cca747ea5cdc68d232
Reviewed-on: https://go-review.googlesource.com/14526
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-09-11 18:31:51 +00:00
Robert Griesemer a370fbaac6 math/big: use more direct formatting in ExampleRoundingMode, cosmetic changes
Change-Id: I3d37391af2089881a5bd4d8f3e5d434b279c272e
Reviewed-on: https://go-review.googlesource.com/14490
Reviewed-by: Chris Manghane <cmang@golang.org>
2015-09-10 22:10:41 +00:00
Konstantin Shaposhnikov e216735dfa math/big: add example for RoundingMode
Updates #11241

Change-Id: I0614c5a9a7a4c399ad5d664f36c70c3210911905
Reviewed-on: https://go-review.googlesource.com/14356
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-09-10 19:58:29 +00:00
Konstantin Shaposhnikov 49fb8cc10c all: minor documentation tweaks for constants
Block comments appear after a block in the HTML documentation generated by
godoc. Words like "following" should be avoided.

Change-Id: Iedfad67f4b8b9c84f128b98b9b06fa76919af388
Reviewed-on: https://go-review.googlesource.com/14357
Reviewed-by: Rob Pike <r@golang.org>
2015-09-09 05:07:52 +00:00
David Leon Gil ea0491b70a math/big: use optimized formula in ModSqrt for 3 mod 4 primes
For primes which are 3 mod 4, using Tonelli-Shanks is slower
and more complicated than using the identity

     a**((p+1)/4) mod p == sqrt(a)

For 2^450-2^225-1 and 2^10860-2^5430-1, which are 3 mod 4:

BenchmarkModSqrt225_TonelliTri      1000     1135375 ns/op
BenchmarkModSqrt225_3Mod4          10000      156009 ns/op
BenchmarkModSqrt5430_Tonelli           1  3448851386 ns/op
BenchmarkModSqrt5430_3Mod4             2   914616710 ns/op

~2.6x to 7x faster.

Fixes #11437 (which is a prime choice of issues to fix)

Change-Id: I813fb29454160483ec29825469e0370d517850c2
Reviewed-on: https://go-review.googlesource.com/11522
Reviewed-by: Adam Langley <agl@golang.org>
2015-08-29 19:11:03 +00:00
Tarmigan Casebolt e893724e75 math: avoid unused assignment in jn.go
Change-Id: Ie4f21bcd5849e994c63ec5bbda2dee6f3ec4da12
Reviewed-on: https://go-review.googlesource.com/13891
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-08-24 14:34:36 +00:00
Robert Griesemer e288271773 math/big: fix TestBytes test
Fixes #12231.

Change-Id: I1f07c444623cd864667e21b2fee534eacdc193bb
Reviewed-on: https://go-review.googlesource.com/13814
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-21 20:02:40 +00:00
Alberto Donizetti 13b5dc885b math/big: correctly handle large exponent in SetString
Even though the umul/uquo functions expect two valid, finite big.Floats
arguments, SetString was calling them with possibly Inf values, which
resulted in bogus return values.

Replace umul and udiv calls with Mul and Quo calls to fix this. Also,
fix two wrong tests.

See relevant issue on issue tracker for a detailed explanation.

Fixes #11341

Change-Id: Ie35222763a57a2d712a5f5f7baec75cab8189a53
Reviewed-on: https://go-review.googlesource.com/13778
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-08-21 18:11:22 +00:00
Robert Griesemer 92eb34b59a math/big: remove superfluous comparison
This is not a functional change.

Also:
- minor cleanups, better comments
- uniform spelling of noun "zeros" (per OED)

Fixes #11277.

Change-Id: I1726f358ce15907bd2410f646b02cf8b11b919cd
Reviewed-on: https://go-review.googlesource.com/11267
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-08-21 17:46:46 +00:00
Andrey Petrov 7cabaded51 math/rand: warn against using package for security-sensitive work
Urge users of math/rand to consider using crypto/rand when doing
security-sensitive work.

Related to issue #11871. While we haven't reached consensus on how
to make the package inherently safer, everyone agrees that the docs
for math/rand can be improved.

Change-Id: I576a312e51b2a3445691da6b277c7b4717173197
Reviewed-on: https://go-review.googlesource.com/12900
Reviewed-by: Rob Pike <r@golang.org>
2015-07-30 12:42:18 +00:00
Robert Griesemer f35bc3ee87 math/big: document rounding for Rat.FloatToString
Fixes #11523.

Change-Id: I172f6facd555a1c6db76f25d5097343c20dea59a
Reviewed-on: https://go-review.googlesource.com/12507
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-07-22 19:47:19 +00:00
Russ Cox bed6326a3c math: fix Log2 test failures on ppc64 (and s390)
- Make Log2 exact for powers of two.
- Fix error tolerance function to make tolerance
  a function of the correct (expected) value.

Fixes #9066.

Change-Id: I0320a93ce4130deed1c7b7685627d51acb7bc56d
Reviewed-on: https://go-review.googlesource.com/12230
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-07-15 05:35:22 +00:00
Brad Fitzpatrick 783297ad6a all: link to https for golang subdomains too
The previous commit (git 2ae77376) just did golang.org.  This one
includes golang.org subdomains like blog, play, and build.

Change-Id: I4469f7b307ae2a12ea89323422044e604c5133ae
Reviewed-on: https://go-review.googlesource.com/12071
Reviewed-by: Rob Pike <r@golang.org>
2015-07-12 04:42:40 +00:00
Brad Fitzpatrick 2ae77376f7 all: link to https instead of http
The one in misc/makerelease/makerelease.go is particularly bad and
probably warrants rotating our keys.

I didn't update old weekly notes, and reverted some changes involving
test code for now, since we're late in the Go 1.5 freeze. Otherwise,
the rest are all auto-generated changes, and all manually reviewed.

Change-Id: Ia2753576ab5d64826a167d259f48a2f50508792d
Reviewed-on: https://go-review.googlesource.com/12048
Reviewed-by: Rob Pike <r@golang.org>
2015-07-11 14:36:33 +00:00
Charlie Dorian 8b221092b9 math: Expm1 returns -1 with large negative argument.
Fixes #11442

Change-Id: I2053fe752c6a122924d28565f1338f73e00ed417
Reviewed-on: https://go-review.googlesource.com/11791
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-07-10 22:22:24 +00:00
Josh Bleecher Snyder 71832ff489 math/rand: improve NewZipf documentation
Change-Id: I78f0f9ac33db153c4a0d7f9866da20ebcd3d3639
Reviewed-on: https://go-review.googlesource.com/11872
Reviewed-by: Rob Pike <r@golang.org>
2015-07-03 21:39:04 +00:00
Andrew Gerrand 895df143a2 math: explain OEIS link
Fixes #10236

Change-Id: Ife85513efda48af81c267b753da2ac7317cdfe75
Reviewed-on: https://go-review.googlesource.com/11479
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-06-26 01:25:58 +00:00
Robert Griesemer 1eb8c4aa44 math/big: fix GCD in presence of aliasing
Fixes #11284.

Change-Id: I4ecc4e4cd3c1b3467b43e4ba9666ea6db5fb61a5
Reviewed-on: https://go-review.googlesource.com/11268
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-06-19 19:53:45 +00:00
Andrew Gerrand 0c247bf41b math/big: refine Fibonacci example
Change-Id: Id9e8c3f89e021b9f389ab3c8403e6a8450fa9f5f
Reviewed-on: https://go-review.googlesource.com/11231
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-06-18 22:16:16 +00:00
ALTree ee1ef8fe67 math/big: Add small complete example of big.Float usage
Updates #11241

Change-Id: I573be85d0cfcf410f6125ecd2be8a3d292c40bbb
Reviewed-on: https://go-review.googlesource.com/11245
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-06-18 21:08:41 +00:00
Robert Griesemer bbf79575a5 math/big: incorporate feedback by josharian (Example_fibonacci)
Change-Id: I376ff39594b532a5490f13e3985b7a6ff4b6761d
Reviewed-on: https://go-review.googlesource.com/11191
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-06-17 20:29:35 +00:00
ALTree f0fee976aa math/big: Added small complete example of big.Int usage
Updates #11241

Change-Id: I9639c4f66cf805a57b087c9f648d3918df105d86
Reviewed-on: https://go-review.googlesource.com/11034
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-06-17 19:42:06 +00:00
Austin Clements 2774b37306 all: use RET instead of RETURN on ppc64
All of the architectures except ppc64 have only "RET" for the return
mnemonic. ppc64 used to have only "RETURN", but commit cf06ea6
introduced RET as a synonym for RETURN to make ppc64 consistent with
the other architectures. However, that commit was never followed up to
make the code itself consistent by eliminating uses of RETURN.

This commit replaces all uses of RETURN in the ppc64 assembly with
RET.

This was done with
    sed -i 's/\<RETURN\>/RET/' **/*_ppc64x.s
plus one manual change to syscall/asm.s.

Change-Id: I3f6c8d2be157df8841d48de988ee43f3e3087995
Reviewed-on: https://go-review.googlesource.com/10672
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
2015-06-06 00:07:23 +00:00
Robert Griesemer c1fed8482d math/big: turn off debug mode
Change-Id: Ie38742cddc5a256e2f0fc0f720c0ed2f1b2e1bca
Reviewed-on: https://go-review.googlesource.com/10664
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-06-03 22:08:17 +00:00
Dave Cheney d15597e1b2 math/big: trim trailing zeros before hex printing
m was being resliced as the result of looking for the first
non zero word of the mantissa, however m was not used later
in printing.

Spotted by Gordon Klaus, https://groups.google.com/forum/#!topic/golang-nuts/MdDLbvOjb4o

Change-Id: Ifbebb51ea5e0d86cb8e0422eb184b8634639a733
Reviewed-on: https://go-review.googlesource.com/10604
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-06-03 22:06:04 +00:00
Robert Griesemer 71cc675572 math/big: implement fmt.Formatter-compatible (*Float).Format
Change-Id: I22fdba8ecaecf4e9201b845e65d982cac09f254a
Reviewed-on: https://go-review.googlesource.com/10499
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-06-02 06:37:53 +00:00
Robert Griesemer a63b1806aa math/big: remove (*Float).Scan, ScanFloat; more robust (*Float).Parse
- (*Float).Scan conflicted with fmt.Scanner.Scan; it was also only used
  internally. Removed it, as well as the companion ScanFloat function.

- (*Float).Parse (and thus ParseFloat) can now also parse infinities.
  As a result, more code could be simplified.

- Fixed a bug in rounding (round may implicitly be called for infinite
  values). Found via existing test cases, after simplifying some code.

- Added more test cases.

Fixes issue #10938.

Change-Id: I1df97821654f034965ba8b82b272e52e6dc427f1
Reviewed-on: https://go-review.googlesource.com/10498
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-29 17:11:43 +00:00
Robert Griesemer 9b3d9230aa math/big: rename (*Float).Format to (*Float).Text
This paves the way for a fmt-compatible (*Float).Format method.
A better name then Text is still desirable (suggestions welcome).

This is partly fixing issue #10938.

Change-Id: I59c20a8cee11f5dba059fe0f38b414fe75f2ab13
Reviewed-on: https://go-review.googlesource.com/10493
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-29 17:10:54 +00:00
Robert Griesemer 0c02b33acd math/big: fix latent decimal conversion bug
A decimal represented 0.0 with a 0-length mantissa and undefined
exponent, but the formatting code assumes a valid zero exponent
if the float value is 0.0. The code worked because we allocate a
new decimal value each time and because there's no rounding that
lead to 0.0.

Change-Id: Ifd771d7709de83b87fdbf141786286b4c3e13d4f
Reviewed-on: https://go-review.googlesource.com/10448
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-28 16:02:32 +00:00
Robert Griesemer 635cd91eb4 math/big: more cleanups (msbxx, nlzxx functions)
Change-Id: Ibace718452b6dc029c5af5240117f5fc794c38cf
Reviewed-on: https://go-review.googlesource.com/10388
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-27 22:10:15 +00:00
Robert Griesemer 0858d8847d math/big: removed TODO, cleanups
- factor out handling of sign
- rename bstring, pstring to fmtB, fmtP consistent with fmtE, fmtF
- move all float-to-string conversion functions into ftoa.go
- no functional changes

Change-Id: I5970ecb874dc9c387630b59147d90bda16a5d8e6
Reviewed-on: https://go-review.googlesource.com/10387
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-27 22:09:47 +00:00
Robert Griesemer 2df1ccdbc6 math/big: Always print exponent sign when using 'p' exponent for Floats.
Float.Format supports the 'b' and 'p' format, both of which print
a binary ('p') exponent. The 'b' format always printed a sign ('+'
or '-') for the exponent; the 'p' format only printed a negative
sign for the exponent. This change makes the two consistent. It
also makes the 'p' format easier to read if the exponent is >= 0.

Also:
- Comments added elsewhere.

Change-Id: Ifd2e01bdafb3043345972ca22a90248d055bd29b
Reviewed-on: https://go-review.googlesource.com/10359
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-22 23:12:51 +00:00
Robert Griesemer 5ffbca4823 math/big: fix Float.Float64 conversion for denormal corner cases
- This change uses the same code as for Float32 and fixes the case
  of a number that gets rounded up to the smallest denormal.

- Enabled correspoding test case.

Change-Id: I8aac874a566cd727863a82717854f603fbdc26c6
Reviewed-on: https://go-review.googlesource.com/10352
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-22 21:10:43 +00:00
Robert Griesemer 8de8925c77 math/big: add more Float.Float64 conversion tests
- structure the Float64 conversion tests the same way as for Float32
- add additional test cases, including one that exposes a current issue
  (currently disabled, same issue as was fixed for Float32)

The Float64 fix will be in a subsequent change for easier reviewing.

Change-Id: I95dc9e8d1f6b6073a98c7bc2289e6d3248fc3420
Reviewed-on: https://go-review.googlesource.com/10351
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-22 21:06:01 +00:00
Robert Griesemer 79afb43a0a math/big: fix Float.Float32 conversion for denormal corner cases
The existing code was incorrect for numbers that after rounding would
become the smallest denormal float32 (instead the result was 0). This
caused all.bash to fail if Float32() were used in the compiler for
constant arithmetic (there's currently a work-around - see also issue
10321.

This change fixes the implementation of Float.Float32 and adds
corresponding test cases. Float32 and Float64 diverge at this point.
For ease of review, this change only fixes Float32. Float64 will be
made to match in a subsequent change.

Fixes #10321.

Change-Id: Iccafe37c1593a4946bc552e4ad2045f69be62d80
Reviewed-on: https://go-review.googlesource.com/10350
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-05-22 21:05:25 +00:00
Robert Griesemer c344f751fc math/big: gofmt nat_test.go
Was apparently checked in by https://go-review.googlesource.com/#/c/9253/
without being gofmt-ed.

TBR: agl

Change-Id: I4d011dbaa15b7c5e73ca71f724f32951a0302dae
Reviewed-on: https://go-review.googlesource.com/10353
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-05-22 01:09:34 +00:00
Vlad Krasnov 9279684908 math/big: Simple Montgomery Multiplication to accelerate Mod-Exp
On Haswell I measure anywhere between 2X to 3.5X speedup for RSA.
I believe other architectures will also greatly improve.
In the future may be upgraded by dedicated assembly routine.

Built-in benchmarks i5-4278U turbo off:

benchmark                         old ns/op     new ns/op     delta
BenchmarkRSA2048Decrypt           6696649       3073769       -54.10%
Benchmark3PrimeRSA2048Decrypt     4472340       1669080       -62.68%

Change-Id: I17df84f85e34208f990665f9f90ea671695b2add
Reviewed-on: https://go-review.googlesource.com/9253
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Vlad Krasnov <vlad@cloudflare.com>
Run-TryBot: Adam Langley <agl@golang.org>
2015-05-22 00:25:25 +00:00
Shenghou Ma 85a1577800 math/big, cmd/internal/gc/big: fix vet detected printf problem
Change-Id: I54425d8cbe0277d7a0c9d66c37f2128a0dfa6441
Reviewed-on: https://go-review.googlesource.com/10041
Run-TryBot: Minux Ma <minux@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-05-14 05:34:40 +00:00
Brad Fitzpatrick f8fbcefa6c math/rand: shorten Float32 test for GOARM=5
Fixes #10749

Change-Id: I9d5f6f179fd117b0c358d7c8042daf5985b645c0
Reviewed-on: https://go-review.googlesource.com/10022
Reviewed-by: Dave Cheney <dave@cheney.net>
2015-05-13 22:31:44 +00:00
Bryan Ford ac61588288 math/big: add modular square-root and Jacobi functions
This change adds Int.ModSqrt to compute modular square-roots via the
standard Tonelli-Shanks algorithm, and the Jacobi function that this and
many other modular-arithmetic algorithms depend on.

This is needed by change 1883 (https://golang.org/cl/1883), to add
support for ANSI-standard compressed encoding of elliptic curve points.

Change-Id: Icc4805001bba0b3cb7200e0b0a7f87b14a9e9439
Reviewed-on: https://go-review.googlesource.com/1886
Reviewed-by: Adam Langley <agl@golang.org>
2015-04-30 04:02:58 +00:00
Josh Bleecher Snyder 56a7c5b95c math/big: add partial arm64 assembly support
benchmark                       old ns/op      new ns/op      delta
BenchmarkAddVV_1                18.7           14.8           -20.86%
BenchmarkAddVV_2                21.8           16.6           -23.85%
BenchmarkAddVV_3                26.1           17.1           -34.48%
BenchmarkAddVV_4                30.4           21.9           -27.96%
BenchmarkAddVV_5                35.5           19.8           -44.23%
BenchmarkAddVV_1e1              63.0           28.3           -55.08%
BenchmarkAddVV_1e2              593            178            -69.98%
BenchmarkAddVV_1e3              5691           1490           -73.82%
BenchmarkAddVV_1e4              56868          20761          -63.49%
BenchmarkAddVV_1e5              569062         207679         -63.51%
BenchmarkAddVW_1                15.8           12.6           -20.25%
BenchmarkAddVW_2                17.8           13.1           -26.40%
BenchmarkAddVW_3                21.2           13.9           -34.43%
BenchmarkAddVW_4                23.6           14.7           -37.71%
BenchmarkAddVW_5                26.0           15.8           -39.23%
BenchmarkAddVW_1e1              41.3           21.6           -47.70%
BenchmarkAddVW_1e2              383            145            -62.14%
BenchmarkAddVW_1e3              3703           1264           -65.87%
BenchmarkAddVW_1e4              36920          14359          -61.11%
BenchmarkAddVW_1e5              370345         143046         -61.37%
BenchmarkAddMulVVW_1            33.2           32.5           -2.11%
BenchmarkAddMulVVW_2            58.0           57.2           -1.38%
BenchmarkAddMulVVW_3            95.2           93.9           -1.37%
BenchmarkAddMulVVW_4            108            106            -1.85%
BenchmarkAddMulVVW_5            159            156            -1.89%
BenchmarkAddMulVVW_1e1          344            340            -1.16%
BenchmarkAddMulVVW_1e2          3644           3624           -0.55%
BenchmarkAddMulVVW_1e3          37344          37208          -0.36%
BenchmarkAddMulVVW_1e4          373295         372170         -0.30%
BenchmarkAddMulVVW_1e5          3438116        3425606        -0.36%
BenchmarkBitLen0                7.21           4.32           -40.08%
BenchmarkBitLen1                6.49           4.32           -33.44%
BenchmarkBitLen2                7.23           4.32           -40.25%
BenchmarkBitLen3                6.49           4.32           -33.44%
BenchmarkBitLen4                7.22           4.32           -40.17%
BenchmarkBitLen5                6.52           4.33           -33.59%
BenchmarkBitLen8                7.22           4.32           -40.17%
BenchmarkBitLen9                6.49           4.32           -33.44%
BenchmarkBitLen16               8.66           4.32           -50.12%
BenchmarkBitLen17               7.95           4.32           -45.66%
BenchmarkBitLen31               8.69           4.32           -50.29%
BenchmarkGCD10x10               5021           5033           +0.24%
BenchmarkGCD10x100              5571           5572           +0.02%
BenchmarkGCD10x1000             6707           6729           +0.33%
BenchmarkGCD10x10000            13526          13419          -0.79%
BenchmarkGCD10x100000           85668          83242          -2.83%
BenchmarkGCD100x100             24196          23936          -1.07%
BenchmarkGCD100x1000            28802          27309          -5.18%
BenchmarkGCD100x10000           64111          51704          -19.35%
BenchmarkGCD100x100000          385840         274385         -28.89%
BenchmarkGCD1000x1000           262892         236269         -10.13%
BenchmarkGCD1000x10000          371393         277883         -25.18%
BenchmarkGCD1000x100000         1311795        589055         -55.10%
BenchmarkGCD10000x10000         9596740        6123930        -36.19%
BenchmarkGCD10000x100000        16404000       7269610        -55.68%
BenchmarkGCD100000x100000       776660000      419270000      -46.02%
BenchmarkHilbert                13478980       13402270       -0.57%
BenchmarkBinomial               9802           9440           -3.69%
BenchmarkBitset                 142            142            +0.00%
BenchmarkBitsetNeg              328            279            -14.94%
BenchmarkBitsetOrig             853            861            +0.94%
BenchmarkBitsetNegOrig          1489           1444           -3.02%
BenchmarkMul                    420949000      410481000      -2.49%
BenchmarkExp3Power0x10          1148           1229           +7.06%
BenchmarkExp3Power0x40          1322           1376           +4.08%
BenchmarkExp3Power0x100         2437           2486           +2.01%
BenchmarkExp3Power0x400         9456           9346           -1.16%
BenchmarkExp3Power0x1000        113623         108701         -4.33%
BenchmarkExp3Power0x4000        1134933        1101481        -2.95%
BenchmarkExp3Power0x10000       10773570       10396160       -3.50%
BenchmarkExp3Power0x40000       101362100      97788300       -3.53%
BenchmarkExp3Power0x100000      921114000      885249000      -3.89%
BenchmarkExp3Power0x400000      8323094000     7969020000     -4.25%
BenchmarkFibo                   322021600      92554450       -71.26%
BenchmarkScanPi                 1264583        321065         -74.61%
BenchmarkStringPiParallel       1644661        554216         -66.30%
BenchmarkScan10Base2            1111           1080           -2.79%
BenchmarkScan100Base2           6645           6345           -4.51%
BenchmarkScan1000Base2          84084          62405          -25.78%
BenchmarkScan10000Base2         3105998        932551         -69.98%
BenchmarkScan100000Base2        257234800      40113333       -84.41%
BenchmarkScan10Base8            571            573            +0.35%
BenchmarkScan100Base8           2810           2543           -9.50%
BenchmarkScan1000Base8          47383          25834          -45.48%
BenchmarkScan10000Base8         2739518        567203         -79.30%
BenchmarkScan100000Base8        253952400      36495680       -85.63%
BenchmarkScan10Base10           553            556            +0.54%
BenchmarkScan100Base10          2640           2385           -9.66%
BenchmarkScan1000Base10         50865          24049          -52.72%
BenchmarkScan10000Base10        3279916        549313         -83.25%
BenchmarkScan100000Base10       309121000      36213140       -88.29%
BenchmarkScan10Base16           478            483            +1.05%
BenchmarkScan100Base16          2353           2144           -8.88%
BenchmarkScan1000Base16         48091          24246          -49.58%
BenchmarkScan10000Base16        2858886        586475         -79.49%
BenchmarkScan100000Base16       266320000      38190500       -85.66%
BenchmarkString10Base2          736            730            -0.82%
BenchmarkString100Base2         2695           2707           +0.45%
BenchmarkString1000Base2        20549          20388          -0.78%
BenchmarkString10000Base2       212638         210782         -0.87%
BenchmarkString100000Base2      1944963        1938033        -0.36%
BenchmarkString10Base8          524            517            -1.34%
BenchmarkString100Base8         1326           1320           -0.45%
BenchmarkString1000Base8        8213           8249           +0.44%
BenchmarkString10000Base8       72204          72092          -0.16%
BenchmarkString100000Base8      769068         765993         -0.40%
BenchmarkString10Base10         1018           982            -3.54%
BenchmarkString100Base10        3485           3206           -8.01%
BenchmarkString1000Base10       37102          18935          -48.97%
BenchmarkString10000Base10      188633         88637          -53.01%
BenchmarkString100000Base10     124490300      19700940       -84.17%
BenchmarkString10Base16         509            502            -1.38%
BenchmarkString100Base16        1084           1098           +1.29%
BenchmarkString1000Base16       5641           5650           +0.16%
BenchmarkString10000Base16      46900          46745          -0.33%
BenchmarkString100000Base16     508957         505840         -0.61%
BenchmarkLeafSize0              8934320        8149465        -8.78%
BenchmarkLeafSize1              237666         118381         -50.19%
BenchmarkLeafSize2              237807         117854         -50.44%
BenchmarkLeafSize3              1688640        353494         -79.07%
BenchmarkLeafSize4              235676         116196         -50.70%
BenchmarkLeafSize5              2121896        430325         -79.72%
BenchmarkLeafSize6              1682306        351775         -79.09%
BenchmarkLeafSize7              1051847        251436         -76.10%
BenchmarkLeafSize8              232697         115674         -50.29%
BenchmarkLeafSize9              2403616        488443         -79.68%
BenchmarkLeafSize10             2120975        429545         -79.75%
BenchmarkLeafSize11             2023789        426525         -78.92%
BenchmarkLeafSize12             1684830        351985         -79.11%
BenchmarkLeafSize13             1465529        337906         -76.94%
BenchmarkLeafSize14             1050498        253872         -75.83%
BenchmarkLeafSize15             683228         197384         -71.11%
BenchmarkLeafSize16             232496         116026         -50.10%
BenchmarkLeafSize32             245841         126671         -48.47%
BenchmarkLeafSize64             301728         190285         -36.93%

Change-Id: I63e63297896d96b89c9a275b893c2b405a7e105d
Reviewed-on: https://go-review.googlesource.com/9260
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-04-23 23:29:15 +00:00
Josh Bleecher Snyder 91f2db3c57 math/big: test that subVW and addVW work with arbitrary y
Fixes #10525.

Change-Id: I92dc87f5d6db396d8dde2220fc37b7093b772d81
Reviewed-on: https://go-review.googlesource.com/9210
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-04-21 23:13:33 +00:00
Robert Griesemer d13f479de3 math/big: better doc strings for ErrNaN functionality
Change-Id: Ia0944e7b47193465d3ec37fc8dc46dea9b5dcc6b
Reviewed-on: https://go-review.googlesource.com/8710
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-04-09 20:18:32 +00:00
Robert Griesemer b28802d2f1 math/big: make ErrNaN actually implement the error interface (oversight)
There was no way to get to the error message before.

Change-Id: I4aa9d3d9f468c33f9996295bafcbed097de0389f
Reviewed-on: https://go-review.googlesource.com/8660
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-04-08 19:47:39 +00:00
ALTree e21154fe31 math/big: fix Exp when exponent is 1
Fixed bug that caused Exp(x, y, m) ( i.e. x**y (mod m) ) to return x
instead of x (mod m) when y == 1. See issue page on github for more
details.

Added test case

Fixes #9826

Change-Id: Ibabb58275a20c4231c9474199b7f1c10e54241ce
Reviewed-on: https://go-review.googlesource.com/8409
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-04-07 21:04:09 +00:00
Igor Dolzhikov debe12cfcf net/http, math/big, cmd/internal/gc/big: replaced errors.New(fmt.Sprintf(...)) in favour fmt.Errorf()
Change-Id: I38fc0ab84a374cb9be0234e40665d7cea0e76fc1
Reviewed-on: https://go-review.googlesource.com/8402
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-04-06 15:40:34 +00:00
Robert Griesemer 09b3bf42c7 math/big: compute 10**exp efficiently when converting Floats
Change-Id: Ic2d9fdae43d18255c198ae62376212bdc89b75da
Reviewed-on: https://go-review.googlesource.com/8464
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-04-04 00:03:16 +00:00
Shenghou Ma 764c751ae5 math, cmd/internal/gc, cmd/7g: enable SQRT inlining, add assembly implementation
benchmark                 old ns/op     new ns/op     delta
BenchmarkSqrt             474           16.5          -96.52%
BenchmarkSqrtIndirect     476           38.1          -92.00%
BenchmarkSqrtGo           484           483           -0.21%

Change-Id: I5ad0132feda0d3275a884523b9e79d83db4fc726
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/8465
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-04-03 23:48:00 +00:00
Russ Cox 92dba0d278 cmd/internal/gc: use hardware instruction for math.Sqrt (amd64/arm)
I first prototyped this change in Sept 2011, and I discarded it
because it made no difference in the obvious benchmark loop.
It still makes no difference in the obvious benchmark loop,
but in a less obvious one, doing some extra computation
around the calls to Sqrt, not making the call does have a
significant effect.

benchmark                 old ns/op     new ns/op     delta
BenchmarkSqrt             4.56          4.57          +0.22%
BenchmarkSqrtIndirect     4.56          4.56          +0.00%
BenchmarkSqrtGo           69.4          69.4          +0.00%
BenchmarkSqrtPrime        4417          3647          -17.43%

This is a warmup for using hardware expansions for some
calls to 1-line assembly routines in the runtime (for example getg).

Change-Id: Ie66be23f8c09d0f7dc4ddd7ca8a93cfce28f55a4
Reviewed-on: https://go-review.googlesource.com/8356
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-03 16:13:36 +00:00
Robert Griesemer bb298754ab math/big: implement missing special cases for binary operations
Change-Id: I9fc12b1a9b1554523e08839c1ff46c8668217ba1
Reviewed-on: https://go-review.googlesource.com/8381
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-04-02 17:05:09 +00:00
Robert Griesemer 919a6fbeab math/big: faster Int.Binomial(n, k) for k > n/2
benchmark             old ns/op     new ns/op     delta
BenchmarkBinomial     478664        4410          -99.08%

Fixes #10084.

Change-Id: Ib75034428e32c79c9a660ae9f9bd396afc6a7f11
Reviewed-on: https://go-review.googlesource.com/8351
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-04-01 19:35:35 +00:00
Robert Griesemer fa85a7206d math/big: remove NaN support - just not worth it
NaNs make the API more complicated for no real good reasons.
There are few operations that produce NaNs with IEEE arithmetic,
there's no need to copy the behavior. It's easy to test for these
scenarios and avoid them (on the other hand, it's not easy to test
for overflow or underflow, so we want to keep +/-Inf).

Also:
- renamed IsNeg -> Signbit (clearer, especially for x == -0)
- removed IsZero           (Sign() == 0 is sufficient and efficient)
- removed IsFinite         (now same as !IsInf)

Change-Id: I3f3b4445c325d9bbb1bf46ce2e298a6aeb498e07
Reviewed-on: https://go-review.googlesource.com/8280
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-31 23:05:31 +00:00
Robert Griesemer 8d267b9b59 math/big: fixed Float.Float64, implemented Float.Float32
- fix bounds checks for exponent range of denormalized numbers
- use correct rounding precision for denormalized numbers
- added extra tests

Change-Id: I6be56399afd0d9a603300a2e44b5539e08d6f592
Reviewed-on: https://go-review.googlesource.com/8096
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-31 19:36:55 +00:00
Jeremy Schlatter ff1f3a11e4 math/big: fix copy-paste mistake in int_test.go
Change-Id: If986ed2cf94efba92763d00a3182047c05d6f805
Reviewed-on: https://go-review.googlesource.com/8133
Reviewed-by: Minux Ma <minux@golang.org>
2015-03-27 21:02:31 +00:00
Robert Griesemer 2c4cf2f6f2 math/big: fix known bug in Float.Float64
- handle exponent over- and underflow
- handle denormalized numbers
- added test cases

Change-Id: I1bbb9904b0c104f54696944e1f57559881f6eeeb
Reviewed-on: https://go-review.googlesource.com/7982
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-24 20:34:14 +00:00
Robert Griesemer 98182c86b1 math/big: enable pure Go (no assembly) build with build tag
To use a pure Go implementation of the low-level arithmetic
functions (when no platform-specific assembly implementations
are available), set the build tag math_big_pure_go.

This will make it easy to vendor the math/big package where no
assembly is available (for instance for use with gc which relies
on 1.4 functionality for now).

Change-Id: I91e17c0fdc568a20ec1512d7c64621241dc60c17
Reviewed-on: https://go-review.googlesource.com/7856
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-03-20 21:58:19 +00:00
Josh Bleecher Snyder 2adc4e8927 all: use "reports whether" in place of "returns true if(f)"
Comment changes only.

Change-Id: I56848814564c4aa0988b451df18bebdfc88d6d94
Reviewed-on: https://go-review.googlesource.com/7721
Reviewed-by: Rob Pike <r@golang.org>
2015-03-18 15:14:06 +00:00
Robert Griesemer db96e6821a math/big: clearer semantics for Float.Scan
Change-Id: I72e8389ec080be8a0119f98df898de6f5510fa4d
Reviewed-on: https://go-review.googlesource.com/7693
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-17 20:18:53 +00:00
Robert Griesemer 00c73f5c6e math/big: cleaner handling of exponent under/overflow
Fixed several corner-case bugs and added corresponding tests.

Change-Id: I23096b9caeeff0956f65ab59fa91e168d0e47bb8
Reviewed-on: https://go-review.googlesource.com/7001
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-17 16:09:34 +00:00
Aram Hăvărneanu f0aef42ea1 math, math/big: add support for GOARCH=arm64
Change-Id: Ief12e1435a40dd2eaddc3f97f63be44c4dd2e050
Reviewed-on: https://go-review.googlesource.com/7144
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-16 18:46:10 +00:00
Robert Griesemer 23fd374bf2 math/big: wrap Float.Cmp result in struct to prevent wrong use
Float.Cmp used to return a value < 0, 0, or > 0 depending on how
arguments x, y compared against each other. With the possibility
of NaNs, the result was changed into an Accuracy (to include Undef).
Consequently, Float.Cmp results could still be compared for (in-)
equality with 0, but comparing if < 0 or > 0 would provide the
wrong answer w/o any obvious notice by the compiler.

This change wraps Float.Cmp results into a struct and accessors
are used to access the desired result. This prevents incorrect
use.

Change-Id: I34e6a6c1859251ec99b5cf953e82542025ace56f
Reviewed-on: https://go-review.googlesource.com/7526
Reviewed-by: Rob Pike <r@golang.org>
2015-03-14 00:48:53 +00:00
Robert Griesemer a4bfe64f00 math/big: fix minor documentation issue
Change-Id: Ib42f75c03573cec16801b79a6eb9b1b542028f4f
Reviewed-on: https://go-review.googlesource.com/7524
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-13 21:30:11 +00:00
Robert Griesemer f6580319e4 math/big: fix silly bug in Int64 accessor
Change-Id: If335d45ea1ab6c8aeeb47515f97680e2c1d651f3
Reviewed-on: https://go-review.googlesource.com/7522
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-13 20:14:57 +00:00
Robert Griesemer 8a6eca43df math/big: handle NaNs in Float.Cmp
Also:
- Implemented NewFloat convenience factory function (analogous to
  NewInt and NewRat).
- Implemented convenience accessors for Accuracy values returned
  from Float.Cmp.
- Added test and example.

Change-Id: I985bb4f86e6def222d4b2505417250d29a39c60e
Reviewed-on: https://go-review.googlesource.com/6970
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-12 18:56:25 +00:00
Robert Griesemer 363617c7d3 math/big: added (internal) Float.form field for easier case distinctions
This is a fairly significant _internal_ representation change. Instead
of encoding 0, finite, infinite, and NaN values with special mantissa
and exponent values, a new (1 byte) 'form' field is used (without making
the Float struct bigger). The form field permits simpler and faster
case distinctions. As a side benefit, for zero and non-finite floats,
fewer fields need to be set. Also, the exponent range is not the full
int32 range (in the old format, infExp and nanExp were used to represent
Inf and NaN values and tests for those values sometimes didn't test
for the empty mantissa, so the range was reduced by 2 values).

The correspondence between the old and new fields is as follows.
Old representation:

x                 neg      mant         exp
---------------------------------------------------------------
+/-0              sign     empty        0
0 < |x| < +Inf    sign     mantissa     exponent
+/-Inf            sign     empty        infExp
NaN               false    empty        nanExp

New representation (- stands for ignored fields):

x                 neg      mant         exp         form
---------------------------------------------------------------
+/-0              sign     -            -           zero
0 < |x| < +Inf    sign     mantissa     exponent    finite
+/-Inf            sign     -            -           inf
NaN               -        -            -           nan

Client should not be affected by this change.

Change-Id: I7e355894d602ceb23f9ec01da755fe6e0386b101
Reviewed-on: https://go-review.googlesource.com/6870
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-12 18:41:45 +00:00
Robert Griesemer 0ff7c3ea45 math/big: make validate a method of Float (cleanup)
Change-Id: If38f45acffd352ed95f32f3a36edd91a1fb33d0c
Reviewed-on: https://go-review.googlesource.com/6850
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-12 18:34:42 +00:00
Robert Griesemer 63269404a8 math/big: introduce Bits abstraction instead of using "untyped" []int bit lists
Change-Id: I6caa6bdcf6643ce3015244397a752bd133f3d00c
Reviewed-on: https://go-review.googlesource.com/6840
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-12 18:31:21 +00:00
Robert Griesemer f3d3328988 math/big: move "bits" operations used for Float tests into separate file
This is a pure code move without any semantic change.

Change-Id: I2c18efc858955d07949b1241e793232f2cf1deb9
Reviewed-on: https://go-review.googlesource.com/6821
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-06 01:36:59 +00:00
Robert Griesemer 85626a9266 math/big: added more comprehensive mul/quo test
Change-Id: Ib813eb5960c3310b1c919f25f687560f4f9d63b0
Reviewed-on: https://go-review.googlesource.com/6820
Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-05 01:36:45 +00:00
Robert Griesemer 7be32d038a math/big: reenable TestFloatAdd32 (used to fail on 32bit platforms)
Change-Id: I932c2f1b1d27c437722cd27d2001b085a655c572
Reviewed-on: https://go-review.googlesource.com/6722
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:24:53 +00:00
Robert Griesemer 2a1728d009 math/big: use stringer for enum String() methods
Change-Id: Ide0615542d67b7d81bf6c56aab550e142a8789f7
Reviewed-on: https://go-review.googlesource.com/6682
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:24:34 +00:00
Robert Griesemer 0a8a625848 math/big: added Float.Add example, remove warning from Floats
Change-Id: If04840c34b0ac5168ce1699eae880f04ae21c84c
Reviewed-on: https://go-review.googlesource.com/6680
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:24:15 +00:00
Robert Griesemer ef0b03137d math/big: remove Float.Lsh/Rsh; added shift example
Shifts are trivially implemented by combining
Float.MantExp and Float.SetMantExp.

Change-Id: Ia2fb49297d8ea7aa7d64c8b1318dc3dc7c8af2f7
Reviewed-on: https://go-review.googlesource.com/6671
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:23:43 +00:00
Robert Griesemer d934d10a0b math/big: introduce Undef Accuracy, use for NaN operands/results
This change represents Accuracy as a bit pattern rather than
an ordered value; with a new value Undef which is both Below
and Above.

Change-Id: Ibb96294c1417fb3cf2c3cf2374c993b0a4e106b3
Reviewed-on: https://go-review.googlesource.com/6650
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:23:22 +00:00
Robert Griesemer ea1fafbccd math/big: modified MantExp semantics to enable fast exponent access
Change-Id: I9a6ebb747d5b9756c214bdeb19f60820602d7a24
Reviewed-on: https://go-review.googlesource.com/6340
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:22:31 +00:00
Robert Griesemer e053883352 math/big: implement NaN
This change introduces NaNs (for situations like Inf-Inf, etc.).
The implementation is incomplete (the four basic operations produce
a NaN if any of the operands is an Inf or a NaN); and some operations
produce incorrect accuracy for NaN arguments. These are known bugs
which are documented.

Change-Id: Ia88841209e47930681cef19f113e178f92ceeb33
Reviewed-on: https://go-review.googlesource.com/6540
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-04 18:22:01 +00:00
Robert Griesemer c3dc78f301 math/big: replace Float.NewInf with Float.SetInf for more consistent API
Change-Id: I2a60ea4a196eef1af5d2aae6cc239c64bddb6fb2
Reviewed-on: https://go-review.googlesource.com/6301
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-03-02 20:35:49 +00:00
Robert Griesemer 79c12958c7 math/big: export Float.MinPrec
MinPrec returns the minimum precision required to represent a Float
without loss of precision. Added test.

Change-Id: I466c8e492dcdd59fae854fc4e71ef9b1add7d817
Reviewed-on: https://go-review.googlesource.com/6010
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-26 17:01:16 +00:00
Robert Griesemer 9c4aade584 math/big: fix build for 32bit platforms
Change-Id: I9c217e5140294a17e4feb65da5b121ee8d8cadc2
Reviewed-on: https://go-review.googlesource.com/6050
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-02-26 00:15:04 +00:00
Robert Griesemer ca0be6f849 math/big: clean up Float.SetPrec, use shorter internal representation
Change-Id: I9b78085adc12cbd240d0b8b48db6810ddb2aeadd
Reviewed-on: https://go-review.googlesource.com/5991
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-25 23:10:44 +00:00
Robert Griesemer c20a018d6f math/big: apply a round of go vet
Change-Id: Ie8310acc783659497e50dfe629f06d655b51d647
Reviewed-on: https://go-review.googlesource.com/5990
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-25 23:10:14 +00:00
Robert Griesemer bba8b89aa5 math/big: improve some doc strings
Change-Id: Ie37673d4af2fa7476d67ffb686641611ab6a8e6b
Reviewed-on: https://go-review.googlesource.com/5930
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-25 23:09:51 +00:00
Robert Griesemer 88cbe09202 math/big: permit passing of an *Int to Float.Int to avoid allocation
Change-Id: I50e83248357928e56c94b88a8764de828f4f5c76
Reviewed-on: https://go-review.googlesource.com/5890
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-25 18:10:42 +00:00
Robert Griesemer 3e9e9b4822 math/big: implemented Float.Rat
Change-Id: If516e12d4b5dfb6f9288437d270569f7e4e2a1cd
Reviewed-on: https://go-review.googlesource.com/5871
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-25 16:53:28 +00:00
Robert Griesemer 18fd940620 math/big: permit passing of (possibly nil) *Float to MantExp to avoid allocation
Change-Id: Ia92eea833283f8b16fa09d4ca1c9cb3bc0eb18a2
Reviewed-on: https://go-review.googlesource.com/5870
Reviewed-by: Rob Pike <r@golang.org>
2015-02-25 00:46:27 +00:00
Robert Griesemer c4b8f9127a math/big: fix test for 32bit platforms (fix build)
Change-Id: I73509cd0e0866cfe2b2ae46a26fb4d043dd050c4
Reviewed-on: https://go-review.googlesource.com/5840
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-02-24 21:58:00 +00:00
Robert Griesemer c651fdc0cf math/big: change Float.SetMantExp to always multiply mant by 2**exp
Change-Id: If840e647376a2141f8c17729f7ef251bfff13f5f
Reviewed-on: https://go-review.googlesource.com/5810
Reviewed-by: Rob Pike <r@golang.org>
2015-02-24 21:30:04 +00:00
Robert Griesemer d9859ad404 math/big: fix several issues with string->Float conversion
Change-Id: I7bf7154e2d8d779fdf7f1d2bb561a06ad174f3b0
Reviewed-on: https://go-review.googlesource.com/4883
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-24 17:35:25 +00:00
Charlie Dorian ec92af650c math: Dim, Max, Min - allow more bit patterns for NaN
Fixes #9919

Change-Id: Ib443c762f727d4986ca7f8a404362f92b0e91aff
Reviewed-on: https://go-review.googlesource.com/5553
Reviewed-by: Minux Ma <minux@golang.org>
2015-02-23 23:07:01 +00:00
Robert Griesemer ce137592c0 math/big: fix formatting for 'b' format
Fixes #9939.

Change-Id: I9d60722b648fbc00650115da539a7466c6c86552
Reviewed-on: https://go-review.googlesource.com/5640
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-23 21:23:50 +00:00
Charles Dorian b48d2a5f25 math: faster Cbrt
Old 45.3 ns/op, new 19.9 ns/op.

Change-Id: If2a201981dcc259846631ecbc694c401e0a80287
Reviewed-on: https://go-review.googlesource.com/5260
Reviewed-by: Russ Cox <rsc@golang.org>
2015-02-23 21:04:46 +00:00
Robert Griesemer 6a10f720f2 math/big: don't return io.EOF on successful call of ParseFloat
Fixes $9938.

Change-Id: Ie8680a875225748abd660fb26b4c25546e7b92d3
Reviewed-on: https://go-review.googlesource.com/5620
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-23 19:20:15 +00:00
Robert Griesemer 2b0213d569 math/big: incorporated feedback from prior TBR reviews
Change-Id: Ida847365223ef09b4a3846e240b4bb6919cb0fe9
Reviewed-on: https://go-review.googlesource.com/5610
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-23 18:09:36 +00:00
Ivan Ukhov 277eddb8f2 math: change Nextafter64 to Nextafter in the description of Nextafter
Change-Id: I3419d6247fbff36aa1ed5451bb3cfb7502c3d07e
Reviewed-on: https://go-review.googlesource.com/5030
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-02-17 14:29:18 +00:00
Robert Griesemer 61c9c3ddc4 math/big: implement fast path in Float.SetRat if argument is integer
Change-Id: Ib82500e198b86e9fade278c7eea7a4b0c6b0b2e1
Reviewed-on: https://go-review.googlesource.com/4921
Reviewed-by: Rob Pike <r@golang.org>
2015-02-15 20:11:00 +00:00
Robert Griesemer 2dd7a6d41f math/big: always round after the sign is set
Some rounding modes are affected by the sign of the value to
be rounded. Make sure the sign is set before round is called.
Added tests (that failed before the fix).

Change-Id: Idd09b8fcbab89894fede0b9bc922cda5ddc87930
Reviewed-on: https://go-review.googlesource.com/4876
Reviewed-by: Rob Pike <r@golang.org>
2015-02-15 05:14:05 +00:00
Robert Griesemer b7bfb54eaa math/big: fix aliasing bug in Float.Quo
TBR r, adonovan

Change-Id: I1a38e2d724bf1147c7307a7e5ae855c42c60428c
Reviewed-on: https://go-review.googlesource.com/4875
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 04:22:56 +00:00
Robert Griesemer a809dc7adb math/big: don't scan past a binary exponent if not accepted syntactically
TBR adonovan

Change-Id: I842cbc855dbd560f65e76c9a557dff1a22c5d610
Reviewed-on: https://go-review.googlesource.com/4882
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 01:01:19 +00:00
Robert Griesemer ccdbfe3174 math/big: only permit bases 2, 10, 16 when scanning number w/ "decimal" point
TBR adonovan

Change-Id: I4fd694101c2cf1c0c39bf73d16cab18502742dd9
Reviewed-on: https://go-review.googlesource.com/4881
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 01:00:30 +00:00
Robert Griesemer 2e3c738649 math/big: remove Float.Round (not needed anymore), fix a bug in SetInt64
TBR adonovan

Change-Id: I30020f39be9183b37275e10a4fd1e1a3b4c48c89
Reviewed-on: https://go-review.googlesource.com/4880
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 00:43:07 +00:00
Robert Griesemer df218d3393 math/big: implement/rename accessors for precision and rounding mode
Also: remove NewFloat - not needed anymore. Work-around for places
where has been used so far:

NewFloat(x, prec, mode) === new(Float).SetMode(mode).SetPrec(prec).SetFloat64(x)

However, if mode == ToNearestEven, SetMode is not needed. SetPrec
is needed if the default precision (53 after SetFloat64) is not
adequate.

TBR adonovan

Change-Id: Ifda12c479ba157f2dea306c32b47c7afbf31e759
Reviewed-on: https://go-review.googlesource.com/4842
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 00:42:40 +00:00
Robert Griesemer 31e852402f math/big: fix aliasing error in Add, Sub
Also:
- make representation more flexible (no need to store trailing 0 digits to match precision)
- simplify rounding as a consequence
- minor related fixes

TBR adonovan

Change-Id: Ie91075990688b506d28371ec3b633b8267397ebb
Reviewed-on: https://go-review.googlesource.com/4841
Reviewed-by: Rob Pike <r@golang.org>
2015-02-14 00:42:05 +00:00
Robert Griesemer 7a77d8d1e9 math/big: use internal validation more consistently
TBR adonovan

Change-Id: If77afa6474af6cad6512f6866725e3ae5acf2e3f
Reviewed-on: https://go-review.googlesource.com/4840
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-02-14 00:41:20 +00:00
Robert Griesemer 9e9ddb004f math/big: implemented Float.Int64, simplified Float.Uint64
Change-Id: Ic270ffa7ec6f6dd4b0a951c64ad965447cce1417
Reviewed-on: https://go-review.googlesource.com/4571
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-12 20:59:02 +00:00
Robert Griesemer 764a9cf20d math/big: completed Float.Uint64
Change-Id: Ib3738492a2ec8fc99323e687168b17b7239db6ad
Reviewed-on: https://go-review.googlesource.com/4511
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-11 17:03:08 +00:00
Robert Griesemer 15fe15a198 math/big: add test cases for Float.Abs and Float.Neg
Change-Id: Ic5f3864bc6d94d60b754e3ccf72b1d40c5c09117
Reviewed-on: https://go-review.googlesource.com/4510
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-11 17:02:54 +00:00
Robert Griesemer 64e7038291 math/big: implemented Float.Int (truncation of Floats to Ints)
Change-Id: Id98f7333fe6ae1b64e0469c6d01f02360c1f8f55
Reviewed-on: https://go-review.googlesource.com/4481
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-11 17:02:35 +00:00
Robert Griesemer 950aa9f1bc math/big: When result prec == 0, use at least prec == 64 for SetInt, SetRat.
This avoids surprises.

Change-Id: Iaae67da2d12e29c4e797ad6313e0895f7ce80cb1
Reviewed-on: https://go-review.googlesource.com/4480
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-11 17:02:09 +00:00
Robert Griesemer f77696a7f0 math/big: implemented Frexp, Ldexp, IsInt, Copy, bug fixes, more tests
- Frexp, Ldexp are equivalents to the corresponding math functions.
- Set now has the same prec behavior as the other functions
- Copy is a true assignment (replaces old version of Set)
- Cmp now handles infinities
- more tests

Change-Id: I0d33980c08be3095b25d7b3d16bcad1aa7abbd0f
Reviewed-on: https://go-review.googlesource.com/4292
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-10 19:08:53 +00:00
Robert Griesemer 04ce9dbf35 math/big: correct umax
Change-Id: I208c8ac44d1a8882d8fdeb18347dc20941e20374
Reviewed-on: https://go-review.googlesource.com/4250
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-09 19:32:12 +00:00
Robert Griesemer acfe3a59bd math/big: API cleanup
- better and more consistent documentation
- more functions implemented
- more tests

Change-Id: If4c591e7af4ec5434fbb411a48dd0f8add993720
Reviewed-on: https://go-review.googlesource.com/4140
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-09 17:53:18 +00:00
Robert Griesemer 15594df6b4 math/big: handling of +/-Inf and zero precision, enable zero values
- clarified representation of +/-Inf
- only 0 and Inf values can have 0 precision
- a zero precision value used as result value takes the max precision
  of the arguments (to be fine-tuned for setters)
- the zero precision approach makes Float zero values possible
  (they represent +0)
- more tests

Missing: Filling in the blanks. More tests.

Change-Id: Ibb4f97e12e1f356c3085ce80f3464e97b82ac130
Reviewed-on: https://go-review.googlesource.com/4000
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-06 17:21:01 +00:00
Péter Surányi 9b6ccb1323 all: don't refer to code.google.com/p/go{,-wiki}/
Only documentation / comment changes. Update references to
point to golang.org permalinks or go.googlesource.com/go.
References in historical release notes under doc are left as is.

Change-Id: Icfc14e4998723e2c2d48f9877a91c5abef6794ea
Reviewed-on: https://go-review.googlesource.com/4060
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-02-06 14:41:47 +00:00
Robert Griesemer f083a0e364 math/big: add "smoke test" for big.Float division
Change-Id: Ica419a1215ca33dc1cff1e9e4137f204591e3cee
Reviewed-on: https://go-review.googlesource.com/3942
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-05 22:22:28 +00:00
Robert Griesemer 91c0f006fc math/big: more Float conversion tests
Change-Id: Ia30886569141ca2e0321bea6ee1d5c9e0f79d6f9
Reviewed-on: https://go-review.googlesource.com/3941
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-05 22:21:01 +00:00
Robert Griesemer 57c1485fd9 math/big: simplified formatting logic
Change-Id: I4329c44b829fcd77e4f1a1d45904f0f8a280a595
Reviewed-on: https://go-review.googlesource.com/3940
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-05 22:19:42 +00:00
Robert Griesemer 721d5893d7 math/big: first version of Float %e, %f, %g, %G formatting working
Change-Id: I10efa3bc8bc7f41100feabe17837f805a42d7eb6
Reviewed-on: https://go-review.googlesource.com/3842
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-04 21:11:51 +00:00
Robert Griesemer b8fcae02b0 math/big: fix %b format so it matches strconf %b format for non-zero values
(For zero values the strconv %b format prints the bias-adjusted exponent;
there's no bias in Float.)

Change-Id: I6f4dda9c3a50d02eac375cfe2c927c1540aae865
Reviewed-on: https://go-review.googlesource.com/3841
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-04 21:07:37 +00:00
Robert Griesemer bbd6771621 math/big: implemented decimal rounding for Float-to-string conversion
Change-Id: Id508ca2f6c087861e8c6bc536bc39e54dce09825
Reviewed-on: https://go-review.googlesource.com/3840
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-04 21:06:37 +00:00
Robert Griesemer 01ba4c000c math/big: implement precise Float to decimal conversion (core functionality)
Change-Id: Ic0153397922ded28a5cb362e86ecdfec42e92163
Reviewed-on: https://go-review.googlesource.com/3752
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-03 19:04:26 +00:00
Robert Griesemer 6966e07ae7 math/big: fix typos
Change-Id: Icb1490f97584d61823339ae809b88d423b185e64
Reviewed-on: https://go-review.googlesource.com/3751
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-03 18:48:38 +00:00
Robert Griesemer 4c91c0d07b math/big: build Float.Format on top of Float.Append
Change-Id: I444eec24467f827caa5c88a1c5ae5bce92508b98
Reviewed-on: https://go-review.googlesource.com/3750
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-02-03 18:43:51 +00:00
Robert Griesemer f17cd88089 math/big: split float conversion routines and tests into separate files
No other functional changes.

Change-Id: I7e0bb7452c6a265535297ec7ce6a629f1aff695c
Reviewed-on: https://go-review.googlesource.com/3674
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-30 23:03:06 +00:00
Robert Griesemer 20a96a1f68 math/big: split rat conversion routines and tests into separate files
No other functional changes.

Change-Id: I8be1fc488caa4f3d4c00afcb8c00475bfcd10709
Reviewed-on: https://go-review.googlesource.com/3673
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-30 23:02:51 +00:00
Robert Griesemer a0c5d28403 math/big: split int conversion routines and tests into separate files
No other functional changes.

Change-Id: If0d9e6208d53478e70d991b6926ea196b2cccf2e
Reviewed-on: https://go-review.googlesource.com/3672
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-30 23:02:35 +00:00
Robert Griesemer d135966ef6 math/big: split nat conversion routines and tests into separate files
No functional changes.

Change-Id: Ibbb705b167603d30467f3ebb83a3bb39845306a5
Reviewed-on: https://go-review.googlesource.com/3671
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-30 23:01:56 +00:00
Robert Griesemer 9f22de7aaf math/big: parsing of fractions and floats in mantissa bases other than 10
Change-Id: I1eaebf956a69e0958201cc5e0a9beefa062c71e1
Reviewed-on: https://go-review.googlesource.com/3454
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-30 21:51:18 +00:00
Robert Griesemer 0a24b8c776 math/big: sketched out complete set of Float/string conversion functions
Also:
- use io.ByteScanner rather than io.RuneScanner internally
- minor simplifications in Float.Add/Sub

Change-Id: Iae0e99384128dba9eccf68592c4fd389e2bd3b4f
Reviewed-on: https://go-review.googlesource.com/3380
Reviewed-by: Rob Pike <r@golang.org>
2015-01-28 23:22:16 +00:00
Robert Griesemer f4a2617765 math/big: various fixes, enable tests for 32bit platforms
- fixed Float.Add, Float.Sub
- fixed Float.PString to be platform independent
- fixed Float.Uint64
- fixed various test outputs

TBR: adonovan

Change-Id: I9d273b344d4786f1fed18862198b23285c358a39
Reviewed-on: https://go-review.googlesource.com/3321
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-27 21:14:42 +00:00
Robert Griesemer 3acb9fd98e math/big: disable some tests on 32bit platforms (fix build)
TBR: adonovan

Change-Id: I59757b5b46a2c533fc5f888423c99d550d3c7648
Reviewed-on: https://go-review.googlesource.com/3264
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-24 05:42:47 +00:00
Robert Griesemer bd275b2381 math/big: multi-precision Floats (starting point)
Implemented:
- +, -, *, /, and some unary ops
- all rounding modes
- basic conversions
- string to float conversion
- tests

Missing:
- float to string conversion, formatting
- handling of +/-0 and +/-inf (under- and overflow)
- various TODOs and cleanups

With precision set to 24 or 53, the results match
float32 or float64 operations exactly (excluding
NaNs and denormalized numbers which will not be
supported).

Change-Id: I3121e90fc4b1528e40bb6ff526008da18b3c6520
Reviewed-on: https://go-review.googlesource.com/1218
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-24 05:17:27 +00:00
Robert Griesemer 2dfa4f4eb0 math/big: use new nat.scan for Rat.SetString
Change-Id: Ida20bf95e8f0fdadb459c2daa6d22edae9c3ad16
Reviewed-on: https://go-review.googlesource.com/3091
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-21 01:48:04 +00:00
Robert Griesemer 4e0618c992 math/big: permit internal nat.scan to accept decimal point
This will simplify parsing of rational and (eventually) floating point numbers.

Also streamlined inner loop. As a result, scan runs faster for all but short
(<= 10 digit) numbers. For short numbers it is < 10% slower (cause is known
and could be addressed in a future CL).

Minor unrelated cleanups. Added additional tests.

benchmark                     old ns/op     new ns/op     delta
BenchmarkScanPi               134465        125122        -6.95%
BenchmarkScan10Base2          493           540           +9.53%
BenchmarkScan100Base2         3608          3244          -10.09%
BenchmarkScan1000Base2        35376         32377         -8.48%
BenchmarkScan10000Base2       481504        450028        -6.54%
BenchmarkScan100000Base2      17936774      17648080      -1.61%
BenchmarkScan10Base8          258           280           +8.53%
BenchmarkScan100Base8         1389          1323          -4.75%
BenchmarkScan1000Base8        14221         13036         -8.33%
BenchmarkScan10000Base8       271298        258993        -4.54%
BenchmarkScan100000Base8      15715465      15672580      -0.27%
BenchmarkScan10Base10         249           268           +7.63%
BenchmarkScan100Base10        1324          1220          -7.85%
BenchmarkScan1000Base10       13398         12234         -8.69%
BenchmarkScan10000Base10      259157        249342        -3.79%
BenchmarkScan100000Base10     15670613      15582409      -0.56%
BenchmarkScan10Base16         231           251           +8.66%
BenchmarkScan100Base16        1093          1065          -2.56%
BenchmarkScan1000Base16       12687         12196         -3.87%
BenchmarkScan10000Base16      282349        271443        -3.86%
BenchmarkScan100000Base16     16742669      16552917      -1.13%

Change-Id: I4b9b078792788aef872b307399f00ffd34903127
Reviewed-on: https://go-review.googlesource.com/2960
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-20 22:57:39 +00:00
Robert Griesemer de47e9ca54 math/big: better test coverage, misc. cleanups
Change-Id: I4ce5cee63093d917095bf90f4e11123f7ec0f93c
Reviewed-on: https://go-review.googlesource.com/2964
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-20 19:23:47 +00:00
Keith Randall c6ddca2aec math/big: bug in AndNot(x,y) for x>0,y<0.
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes #9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-16 17:36:29 +00:00
Robert Griesemer 654a185f20 math/big: faster assembly kernels for AddVx/SubVx for 386.
(analog to Change-Id: Ia473e9ab9c63a955c252426684176bca566645ae)

Fixes #9243.

benchmark              old ns/op     new ns/op     delta
BenchmarkAddVV_1       5.76          5.60          -2.78%
BenchmarkAddVV_2       7.17          6.98          -2.65%
BenchmarkAddVV_3       8.69          8.57          -1.38%
BenchmarkAddVV_4       10.5          10.5          +0.00%
BenchmarkAddVV_5       13.3          11.6          -12.78%
BenchmarkAddVV_1e1     20.4          19.3          -5.39%
BenchmarkAddVV_1e2     166           140           -15.66%
BenchmarkAddVV_1e3     1588          1278          -19.52%
BenchmarkAddVV_1e4     16138         12657         -21.57%
BenchmarkAddVV_1e5     167608        127836        -23.73%
BenchmarkAddVW_1       4.87          4.76          -2.26%
BenchmarkAddVW_2       6.10          6.07          -0.49%
BenchmarkAddVW_3       7.75          7.65          -1.29%
BenchmarkAddVW_4       9.30          9.39          +0.97%
BenchmarkAddVW_5       10.8          10.9          +0.93%
BenchmarkAddVW_1e1     18.8          18.8          +0.00%
BenchmarkAddVW_1e2     143           134           -6.29%
BenchmarkAddVW_1e3     1390          1266          -8.92%
BenchmarkAddVW_1e4     13877         12545         -9.60%
BenchmarkAddVW_1e5     155330        125432        -19.25%

benchmark              old MB/s     new MB/s     speedup
BenchmarkAddVV_1       5556.09      5715.12      1.03x
BenchmarkAddVV_2       8926.55      9170.64      1.03x
BenchmarkAddVV_3       11042.15     11201.77     1.01x
BenchmarkAddVV_4       12168.21     12245.50     1.01x
BenchmarkAddVV_5       12041.39     13805.73     1.15x
BenchmarkAddVV_1e1     15659.65     16548.18     1.06x
BenchmarkAddVV_1e2     19268.57     22728.64     1.18x
BenchmarkAddVV_1e3     20141.45     25033.36     1.24x
BenchmarkAddVV_1e4     19827.86     25281.92     1.28x
BenchmarkAddVV_1e5     19092.06     25031.92     1.31x
BenchmarkAddVW_1       822.12       840.92       1.02x
BenchmarkAddVW_2       1310.89      1317.89      1.01x
BenchmarkAddVW_3       1549.31      1568.26      1.01x
BenchmarkAddVW_4       1720.45      1703.77      0.99x
BenchmarkAddVW_5       1857.12      1828.66      0.98x
BenchmarkAddVW_1e1     2126.39      2132.38      1.00x
BenchmarkAddVW_1e2     2784.49      2969.21      1.07x
BenchmarkAddVW_1e3     2876.89      3157.35      1.10x
BenchmarkAddVW_1e4     2882.32      3188.51      1.11x
BenchmarkAddVW_1e5     2575.16      3188.96      1.24x

(measured on OS X 10.9.5, 2.3 GHz Intel Core i7, 8GB 1333 MHz DDR3)

Change-Id: I46698729d5e0bc3e277aa0146a9d7a086c0c26f1
Reviewed-on: https://go-review.googlesource.com/2560
Reviewed-by: Keith Randall <khr@golang.org>
2015-01-08 20:58:59 +00:00
Robert Griesemer 067acd51b0 math/big: faster "pure Go" addition/subtraction for long vectors
(platforms w/o corresponding assembly kernels)

For short vector adds there's some erradic slow-down, but overall
these routines have become significantly faster. This only matters
for platforms w/o native (assembly) versions of these kernels, so
we are not concerned about the minor slow-down for short vectors.

This code was already reviewed under Mercurial (golang.org/cl/172810043)
but wasn't submitted before the switch to git.

Benchmarks run on 2.3GHz Intel Core i7, running OS X 10.9.5,
with the respective AddVV and AddVW assembly routines disabled.

benchmark              old ns/op     new ns/op     delta
BenchmarkAddVV_1       6.59          7.09          +7.59%
BenchmarkAddVV_2       10.3          10.1          -1.94%
BenchmarkAddVV_3       10.9          12.6          +15.60%
BenchmarkAddVV_4       13.9          15.6          +12.23%
BenchmarkAddVV_5       16.8          17.3          +2.98%
BenchmarkAddVV_1e1     29.5          29.9          +1.36%
BenchmarkAddVV_1e2     246           232           -5.69%
BenchmarkAddVV_1e3     2374          2185          -7.96%
BenchmarkAddVV_1e4     58942         22292         -62.18%
BenchmarkAddVV_1e5     668622        225279        -66.31%
BenchmarkAddVW_1       6.81          5.58          -18.06%
BenchmarkAddVW_2       7.69          6.86          -10.79%
BenchmarkAddVW_3       9.56          8.32          -12.97%
BenchmarkAddVW_4       12.1          9.53          -21.24%
BenchmarkAddVW_5       13.2          10.9          -17.42%
BenchmarkAddVW_1e1     23.4          18.0          -23.08%
BenchmarkAddVW_1e2     175           141           -19.43%
BenchmarkAddVW_1e3     1568          1266          -19.26%
BenchmarkAddVW_1e4     15425         12596         -18.34%
BenchmarkAddVW_1e5     156737        133539        -14.80%
BenchmarkFibo          381678466     132958666     -65.16%

benchmark              old MB/s     new MB/s     speedup
BenchmarkAddVV_1       9715.25      9028.30      0.93x
BenchmarkAddVV_2       12461.72     12622.60     1.01x
BenchmarkAddVV_3       17549.64     15243.82     0.87x
BenchmarkAddVV_4       18392.54     16398.29     0.89x
BenchmarkAddVV_5       18995.23     18496.57     0.97x
BenchmarkAddVV_1e1     21708.98     21438.28     0.99x
BenchmarkAddVV_1e2     25956.53     27506.88     1.06x
BenchmarkAddVV_1e3     26947.93     29286.66     1.09x
BenchmarkAddVV_1e4     10857.96     28709.46     2.64x
BenchmarkAddVV_1e5     9571.91      28409.21     2.97x
BenchmarkAddVW_1       1175.28      1433.98      1.22x
BenchmarkAddVW_2       2080.01      2332.54      1.12x
BenchmarkAddVW_3       2509.28      2883.97      1.15x
BenchmarkAddVW_4       2646.09      3356.83      1.27x
BenchmarkAddVW_5       3020.69      3671.07      1.22x
BenchmarkAddVW_1e1     3425.76      4441.40      1.30x
BenchmarkAddVW_1e2     4553.17      5642.96      1.24x
BenchmarkAddVW_1e3     5100.14      6318.72      1.24x
BenchmarkAddVW_1e4     5186.15      6350.96      1.22x
BenchmarkAddVW_1e5     5104.07      5990.74      1.17x

Change-Id: I7a62023b1105248a0e85e5b9819d3fd4266123d4
Reviewed-on: https://go-review.googlesource.com/2480
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-01-08 17:00:59 +00:00
Robert Griesemer 80b3ff9f82 math/big: faster assembly kernels for AddVx/SubVx for amd64.
Replaced use of rotate instructions (RCRQ, RCLQ) with ADDQ/SBBQ
for restoring/saving the carry flag per suggestion from Torbjörn
Granlund (author of GMP bignum libs for C).
The rotate instructions tend to be slower on todays machines.

benchmark              old ns/op     new ns/op     delta
BenchmarkAddVV_1       5.69          5.51          -3.16%
BenchmarkAddVV_2       7.15          6.87          -3.92%
BenchmarkAddVV_3       8.69          8.06          -7.25%
BenchmarkAddVV_4       8.10          8.13          +0.37%
BenchmarkAddVV_5       8.37          8.47          +1.19%
BenchmarkAddVV_1e1     13.1          12.0          -8.40%
BenchmarkAddVV_1e2     78.1          69.4          -11.14%
BenchmarkAddVV_1e3     815           656           -19.51%
BenchmarkAddVV_1e4     8137          7345          -9.73%
BenchmarkAddVV_1e5     100127        93909         -6.21%
BenchmarkAddVW_1       4.86          4.71          -3.09%
BenchmarkAddVW_2       5.67          5.50          -3.00%
BenchmarkAddVW_3       6.51          6.34          -2.61%
BenchmarkAddVW_4       6.69          6.66          -0.45%
BenchmarkAddVW_5       7.20          7.21          +0.14%
BenchmarkAddVW_1e1     10.0          9.34          -6.60%
BenchmarkAddVW_1e2     45.4          52.3          +15.20%
BenchmarkAddVW_1e3     417           491           +17.75%
BenchmarkAddVW_1e4     4760          4852          +1.93%
BenchmarkAddVW_1e5     69107         67717         -2.01%

benchmark              old MB/s      new MB/s      speedup
BenchmarkAddVV_1       11241.82      11610.28      1.03x
BenchmarkAddVV_2       17902.68      18631.82      1.04x
BenchmarkAddVV_3       22082.43      23835.64      1.08x
BenchmarkAddVV_4       31588.18      31492.06      1.00x
BenchmarkAddVV_5       38229.90      37783.17      0.99x
BenchmarkAddVV_1e1     48891.67      53340.91      1.09x
BenchmarkAddVV_1e2     81940.61      92191.86      1.13x
BenchmarkAddVV_1e3     78443.09      97480.44      1.24x
BenchmarkAddVV_1e4     78644.18      87129.50      1.11x
BenchmarkAddVV_1e5     63918.48      68150.84      1.07x
BenchmarkAddVW_1       13165.09      13581.00      1.03x
BenchmarkAddVW_2       22588.04      23275.41      1.03x
BenchmarkAddVW_3       29483.82      30303.96      1.03x
BenchmarkAddVW_4       38286.54      38453.21      1.00x
BenchmarkAddVW_5       44414.57      44370.59      1.00x
BenchmarkAddVW_1e1     63816.84      68494.08      1.07x
BenchmarkAddVW_1e2     140885.41     122427.16     0.87x
BenchmarkAddVW_1e3     153258.31     130325.28     0.85x
BenchmarkAddVW_1e4     134447.63     131904.02     0.98x
BenchmarkAddVW_1e5     92609.41      94509.88      1.02x

Change-Id: Ia473e9ab9c63a955c252426684176bca566645ae
Reviewed-on: https://go-review.googlesource.com/2503
Reviewed-by: Keith Randall <khr@golang.org>
2015-01-08 16:57:11 +00:00
Shenghou Ma 43178697db math/big: panic if n <= 0 for ProbablyPrime
Fixes #9509

Change-Id: I3b86745d38e09093fe2f4b918d774bd6608727d7
Reviewed-on: https://go-review.googlesource.com/2313
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-01-05 23:11:35 +00:00
Fazlul Shahriar e6f76aac32 math: be consistent in how we document special cases
Change-Id: Ic6bc4af7bcc89b2881b2b9e7290aeb6fd54804e2
Reviewed-on: https://go-review.googlesource.com/2239
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-01-05 21:01:46 +00:00
Guobiao Mei 59cb2d9ca6 math/rand: fix example_test to show with the correct method
Originally it used r.Int63() to show "Uint32", and now we use the correct r.Uint32() method.

Fixes #9429

Change-Id: I8a1228f1ca1af93b0e3104676fc99000257c456f
Reviewed-on: https://go-review.googlesource.com/2069
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2014-12-23 17:24:24 +00:00
Alberto Donizetti 5de497bc6f math: Added parity check to ProbablyPrime
Fixes #9269

Change-Id: I25751632e95978537b656aedfa5c35ab2273089b
Reviewed-on: https://go-review.googlesource.com/1380
Reviewed-by: Robert Griesemer <gri@golang.org>
2014-12-12 00:25:16 +00:00
Russ Cox 09d92b6bbf all: power64 is now ppc64
Fixes #8654.

LGTM=austin
R=austin
CC=golang-codereviews
https://golang.org/cl/180600043
2014-12-05 19:13:20 -05:00
Austin Clements 062e354c84 [dev.power64] runtime: power64 fixes and ports of changes
Fix include paths that got moved in the great pkg/ rename.  Add
missing runtime/arch_* files for power64.  Port changes that
happened on default since branching to
runtime/{asm,atomic,sys_linux}_power64x.s (precise stacks,
calling convention change, various new and deleted functions.
Port struct renaming and fix some bugs in
runtime/defs_linux_power64.h.

LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/161450043
2014-10-27 17:27:03 -04:00
Austin Clements f0bd539c59 [dev.power64] all: merge default into dev.power64
This brings dev.power64 up-to-date with the current tip of
default.  go_bootstrap is still panicking with a bad defer
when initializing the runtime (even on amd64).

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/152570049
2014-10-22 15:51:54 -04:00
Austin Clements 2bd616b1a7 build: merge the great pkg/ rename into dev.power64
This also removes pkg/runtime/traceback_lr.c, which was ported
to Go in an earlier commit and then moved to
runtime/traceback.go.

Reviewer: rsc@golang.org
          rsc: LGTM
2014-10-22 13:25:37 -04:00
Keith Randall 96d1e4ab59 math/big: Allow non-prime modulus for ModInverse
The inverse is defined whenever the element and the
modulus are relatively prime.  The code already handles
this situation, but the spec does not.

Test that it does indeed work.

Fixes #8875

LGTM=agl
R=agl
CC=golang-codereviews
https://golang.org/cl/155010043
2014-10-14 14:09:56 -07:00
Casey Marshall 7371153321 math/big: Fixes issue 8920
(*Rat).SetString checks for denominator.

LGTM=gri
R=golang-codereviews, gri
CC=golang-codereviews
https://golang.org/cl/159760043
2014-10-13 12:41:14 -07:00
Robert Griesemer 87f51f1031 math/big: fix doc comments
Fixes #8904.

TBR=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/148650043
2014-10-07 10:56:58 -07:00
Robert Griesemer 28ddfb090c math/big: math.Exp should return result >= 0 for |m| > 0
The documentation states that Exp(x, y, m)
computes x**y mod |m| for m != nil && m > 0.
In math.big, Mod is the Euclidean modulus,
which is always >= 0.

Fixes #8822.

LGTM=agl, r, rsc
R=agl, r, rsc
CC=golang-codereviews
https://golang.org/cl/145650043
2014-10-02 13:02:25 -07:00
Russ Cox 4a8cb4a49c math: avoid assumption of denormalized math mode in Sincos
The extra-clever code in Sincos is trying to do

        if v&2 == 0 {
                mask = 0xffffffffffffffff
        } else {
                mask = 0
        }

It does this by turning v&2 into a float64 X0 and then using

        MOVSD $0.0, X3
        CMPSD X0, X3, 0

That CMPSD is defined to behave like:

        if X0 == X3 {
                X3 = 0xffffffffffffffff
        } else {
                X3 = 0
        }

which gives the desired mask in X3. The goal in using the
CMPSD was to avoid a conditional branch.

This code fails when called from a PortAudio callback.
In particular, the failure behavior is exactly as if the
CMPSD always chose the 'true' execution.

Notice that the comparison X0 == X3 is comparing as
floating point values the 64-bit pattern v&2 and the actual
floating point value zero. The only possible values for v&2
are 0x0000000000000000 (floating point zero)
and 0x0000000000000002 (floating point 1e-323, a denormal).
If they are both comparing equal to zero, I conclude that
in a PortAudio callback (whatever that means), the processor
is running in "denormals are zero" mode.

I confirmed this by placing the processor into that mode
and running the test case in the bug; it produces the
incorrect output reported in the bug.

In general, if a Go program changes the floating point math
modes to something other than what Go expects, the math
library is not going to work exactly as intended, so we might
be justified in not fixing this at all.

However, it seems reasonable that the client code might
have expected "denormals are zero" mode to only affect
actual processing of denormals. This code has produced
what is in effect a gratuitous denormal by being extra clever.
There is nothing about the computation being requested
that fundamentally requires a denormal.

It is also easy to do this computation in integer math instead:

        mask = ((v&2)>>1)-1

Do that.

For the record, the other math tests that fail if you put the
processor in "denormals are zero" mode are the tests for
Frexp, Ilogb, Ldexp, Logb, Log2, and FloatMinMax, but all
fail processing denormal inputs. Sincos was the only function
for which that mode causes incorrect behavior on non-denormal inputs.

The existing tests check that the new assembly is correct.
There is no test for behavior in "denormals are zero" mode,
because I don't want to add assembly to change that.

Fixes #8623.

LGTM=josharian
R=golang-codereviews, josharian
CC=golang-codereviews, iant, r
https://golang.org/cl/151750043
2014-09-26 17:13:24 -04:00
Russ Cox c007ce824d build: move package sources from src/pkg to src
Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.
2014-09-08 00:08:51 -04:00