The previous s value could cause a crash
for certain inputs.
Will check in tests and documentation improvements later.
Thanks to the Go Ethereum team and the OSS-Fuzz project for reporting this.
Thanks to Rémy Oudompheng and Robert Griesemer for their help
developing and validating the fix.
Fixes CVE-2020-28362
Change-Id: Ibbf455c4436bcdb07c84a34fa6551fb3422356d3
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/899974
Reviewed-by: Roland Shoemaker <bracewell@google.com>
Reviewed-by: Filippo Valsorda <valsorda@google.com>
(cherry picked from commit 28015462c2a83239543dc2bef651e9a5f234b633)
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/901065
Replaced almost every use of Bytes with FillBytes.
Note that the approved proposal was for
func (*Int) FillBytes(buf []byte)
while this implements
func (*Int) FillBytes(buf []byte) []byte
because the latter was far nicer to use in all callsites.
Fixes#35833
Change-Id: Ia912df123e5d79b763845312ea3d9a8051343c0a
Reviewed-on: https://go-review.googlesource.com/c/go/+/230397
Reviewed-by: Robert Griesemer <gri@golang.org>
Originally, we use an assembly function that returns a boolean result to
tell whether the machine has vector facility or not. It is now no longer
needed when we can directly use cpu.S390X.HasVX variable.
Change-Id: Ic1dae851982532bcfd9a9453416c112347f21d87
Reviewed-on: https://go-review.googlesource.com/c/go/+/230318
Reviewed-by: Michael Munday <mike.munday@ibm.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL looks big but it only does formatting changes to arith_s390x.s.
The file was formatted using asmfmt(https://github.com/klauspost/asmfmt)
, so there should not be any functional impact. I verified that the
generated assembly of big.test file is identical.
Change-Id: I8b4035ef082a4d0357881869327e25253f2d8be1
Reviewed-on: https://go-review.googlesource.com/c/go/+/229302
Reviewed-by: Michael Munday <mike.munday@ibm.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The Float.Sqrt method switches (for performance reasons) between
direct (uses Quo) and inverse (doesn't) computation, depending on the
precision, with threshold 128.
Unfortunately the implementation of recursive division in CL 172018
made Quo slightly slower exactly in the range around and below the
threshold Sqrt is using, so this strategy is no longer profitable.
The new division algorithm allocates more, and this has increased the
amount of allocations performed by Sqrt when using the direct method;
on low precisions the computation is fast, so additional allocations
have an negative impact on performance.
Interestingly, only using the inverse method doesn't just reverse the
effects of the Quo algorithm change, but it seems to make performances
better overall for small precisions:
name old time/op new time/op delta
FloatSqrt/64-4 643ns ± 1% 635ns ± 1% -1.24% (p=0.000 n=10+10)
FloatSqrt/128-4 1.44µs ± 1% 1.02µs ± 1% -29.25% (p=0.000 n=10+10)
FloatSqrt/256-4 1.49µs ± 1% 1.49µs ± 1% ~ (p=0.752 n=10+10)
FloatSqrt/1000-4 3.71µs ± 1% 3.74µs ± 1% +0.87% (p=0.001 n=10+10)
FloatSqrt/10000-4 35.3µs ± 1% 35.6µs ± 1% +0.82% (p=0.002 n=10+9)
FloatSqrt/100000-4 844µs ± 1% 844µs ± 0% ~ (p=0.549 n=10+9)
FloatSqrt/1000000-4 69.5ms ± 0% 69.6ms ± 0% ~ (p=0.222 n=9+9)
name old alloc/op new alloc/op delta
FloatSqrt/64-4 280B ± 0% 200B ± 0% -28.57% (p=0.000 n=10+10)
FloatSqrt/128-4 504B ± 0% 248B ± 0% -50.79% (p=0.000 n=10+10)
FloatSqrt/256-4 344B ± 0% 344B ± 0% ~ (all equal)
FloatSqrt/1000-4 1.30kB ± 0% 1.30kB ± 0% ~ (all equal)
FloatSqrt/10000-4 13.5kB ± 0% 13.5kB ± 0% ~ (p=0.237 n=10+10)
FloatSqrt/100000-4 123kB ± 0% 123kB ± 0% ~ (p=0.247 n=10+10)
FloatSqrt/1000000-4 1.83MB ± 1% 1.83MB ± 3% ~ (p=0.779 n=8+10)
name old allocs/op new allocs/op delta
FloatSqrt/64-4 8.00 ± 0% 5.00 ± 0% -37.50% (p=0.000 n=10+10)
FloatSqrt/128-4 11.0 ± 0% 5.0 ± 0% -54.55% (p=0.000 n=10+10)
FloatSqrt/256-4 5.00 ± 0% 5.00 ± 0% ~ (all equal)
FloatSqrt/1000-4 6.00 ± 0% 6.00 ± 0% ~ (all equal)
FloatSqrt/10000-4 6.00 ± 0% 6.00 ± 0% ~ (all equal)
FloatSqrt/100000-4 6.00 ± 0% 6.00 ± 0% ~ (all equal)
FloatSqrt/1000000-4 10.3 ±13% 10.3 ±13% ~ (p=1.000 n=10+10)
For example, 1.02µs for FloatSqrt/128 is actually better than what I
was getting on the same machine before the Quo changes.
The .8% slowdown on /1000 and /10000 appears to be real and it is
quite baffling (that codepath was not touched at all); it may be
caused by code alignment changes.
Change-Id: Ib03761cdc1055674bc7526d4f3a23d7a25094029
Reviewed-on: https://go-review.googlesource.com/c/go/+/228062
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Fixes#38304
Also change `If m > 0, y < 0, ...` to `If m != 0, y < 0, ...` since `Exp` will return `nil`
whatever `m`'s sign is.
Change-Id: I17d7337ccd1404318cea5d42a8de904ad185fd00
GitHub-Last-Rev: 2399510300
GitHub-Pull-Request: golang/go#38390
Reviewed-on: https://go-review.googlesource.com/c/go/+/228000
Reviewed-by: Robert Griesemer <gri@golang.org>
The divBasic function computes the quotient of big nats u/v word by word.
It estimates each word qhat by performing a long division (top 2 words of u
divided by top word of v), looks at the next word to correct the estimate,
then perform a full multiplication (qhat*v) to catch any inaccuracy in the
estimate.
In the latter case, "negative" values appear temporarily and carries
must be carefully managed, and the recursive division refactoring
introduced a case where qhat*v has the same length as v, triggering an
out-of-bounds write in the case it happens when computing the top word
of the quotient.
Fixes#37499
Change-Id: I15089da4a4027beda43af497bf6de261eb792f94
Reviewed-on: https://go-review.googlesource.com/c/go/+/221980
Reviewed-by: Robert Griesemer <gri@golang.org>
Document that the Float.Sqrt method does not set the receiver's
Accuracy field.
Updates #37915
Change-Id: Ief1dcac07eacc0ef02f86bfac9044501477bca1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/224497
Reviewed-by: Robert Griesemer <gri@golang.org>
Provide an assembly implementation of mulWW - for now all others run the
Go code.
Change-Id: Icb594c31048255f131bdea8d64f56784fc9db4d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/220919
Reviewed-by: Robert Griesemer <gri@golang.org>
It was removed in CL 217302 but was intentionally added in CL 217104.
Change-Id: I1a478d80ad1ec4f0a0184bfebf8f1a5e352cfe8c
Reviewed-on: https://go-review.googlesource.com/c/go/+/217941
Reviewed-by: Robert Griesemer <gri@golang.org>
We don't usually document past behavior (like "As of Go 1.14 ...") and
in isolation the current docs made it sound like a and b could only be
negative or zero.
Change-Id: I0d3c2b8579a9c01159ce528a3128b1478e99042a
Reviewed-on: https://go-review.googlesource.com/c/go/+/217302
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The bounds in the last carry branch were wrong as there
is no reason for len(u) >= n+n/2 to always hold true.
We also adjust test to avoid using a remainder of 1
(in which case, the last step of the algorithm computes
(qhatv+1) - qhatv which rarely produces a carry).
Change-Id: I69fbab9c5e19d0db1c087fbfcd5b89352c2d26fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/206839
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
There is a (theoretical, but possible) chance that the
random number values a, b used for TestDiv are 0 or 1,
in which case the test would fail.
This CL makes sure that a >= 1 and b >= 2 at all times.
Fixes#35523.
Change-Id: I6451feb94241249516a821cd0066e95a0c65b0ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/206818
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The current division algorithm produces one word of result at a time,
using 2-word division to compute the top word and mulAddVWW to compute
the remainder. The top word may need to be adjusted by 1 or 2 units.
The recursive version, based on Burnikel, Ziegler, "Fast Recursive Division",
uses the same principles, but in a multi-word setting, so that
multiplication benefits from the Karatsuba algorithm (and possibly later
improvements).
benchmark old ns/op new ns/op delta
BenchmarkDiv/20/10-4 38.2 38.3 +0.26%
BenchmarkDiv/40/20-4 38.7 38.5 -0.52%
BenchmarkDiv/100/50-4 62.5 62.6 +0.16%
BenchmarkDiv/200/100-4 238 259 +8.82%
BenchmarkDiv/400/200-4 311 338 +8.68%
BenchmarkDiv/1000/500-4 604 649 +7.45%
BenchmarkDiv/2000/1000-4 1214 1278 +5.27%
BenchmarkDiv/20000/10000-4 38279 36510 -4.62%
BenchmarkDiv/200000/100000-4 3022057 1359615 -55.01%
BenchmarkDiv/2000000/1000000-4 310827664 54012939 -82.62%
BenchmarkDiv/20000000/10000000-4 33272829421 1965401359 -94.09%
BenchmarkString/10/Base10-4 158 156 -1.27%
BenchmarkString/100/Base10-4 797 792 -0.63%
BenchmarkString/1000/Base10-4 3677 3814 +3.73%
BenchmarkString/10000/Base10-4 16633 17116 +2.90%
BenchmarkString/100000/Base10-4 5779029 1793808 -68.96%
BenchmarkString/1000000/Base10-4 889840820 85524031 -90.39%
BenchmarkString/10000000/Base10-4 134338236860 4935657026 -96.33%
Fixes#21960
Updates #30943
Change-Id: I134c6f81a47870c688ca95b6081eb9211def15a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/172018
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Allow the inputs a and b to be zero or negative to GCD
with the following definitions.
If x or y are not nil, GCD sets their value such that z = a*x + b*y.
Regardless of the signs of a and b, z is always >= 0.
If a == b == 0, GCD sets z = x = y = 0.
If a == 0 and b != 0, GCD sets z = |b|, x = 0, y = sign(b) * 1.
If a != 0 and b == 0, GCD sets z = |a|, x = sign(a) * 1, y = 0.
Fixes#28878
Change-Id: Ia83fce66912a96545c95cd8df0549bfd852652f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/164972
Run-TryBot: Brian Kessler <brian.m.kessler@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
A Rat is represented via a quotient a/b where a and b are Int values.
To make it possible to use an uninitialized Rat value (with a and b
uninitialized and thus == 0), the implementation treats a 0 denominator
as 1.
Rat.Num and Rat.Denom return pointers to these values a and b. Because
b may be 0, Rat.Denom used to first initialize it to 1 and thus produce
an undesirable side-effect (by changing the Rat's denominator).
This CL changes Denom to return a new (not shared) *Int with value 1
in the rare case where the Rat was not initialized. This eliminates
the side effect and returns the correct denominator value.
While this is changing behavior of the API, the impact should now be
minor because together with (prior) CL https://golang.org/cl/202997,
which initializes Rats ASAP, Denom is unlikely used to access the
denominator of an uninitialized (and thus 0) Rat. Any operation that
will somehow set a Rat value will ensure that the denominator is not 0.
Fixes#33792.
Updates #3521.
Change-Id: I0bf15ac60513cf52162bfb62440817ba36f0c3fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/203059
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
A Rat is represented via a quotient a/b where a and b are Int values.
To make it possible to use an uninitialized Rat value (with a and b
uninitialized and thus == 0), the implementation treats a 0 denominator
as 1.
For each operation we check if the denominator is 0, and then treat
it as 1 (if necessary). Operations that create a new Rat result,
normalize that value such that a result denominator 1 is represened
as 0 again.
This CL changes this behavior slightly: 0 denominators are still
interpreted as 1, but whenever we (safely) can, we set an uninitialized
0 denominator to 1. This simplifies the code overall.
Also: Improved some doc strings.
Preparation for addressing issue #33792.
Updates #33792.
Change-Id: I3040587c8d0dad2e840022f96ca027d8470878a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/202997
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Do not modify the underlying Rat denominator when calling
one of the accessors Float32, Float64; verify that we don't
modify the Rat denominator when calling Inv, Sign, IsInt, Num.
Fixes#34919.
Reopens#33792.
Change-Id: Ife6d1252373f493a597398ee51e7b5695b708df5
Reviewed-on: https://go-review.googlesource.com/c/go/+/201205
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is part two if the nacl removal. Part 1 was CL 199499.
This CL removes amd64p32 support, which might be useful in the future
if we implement the x32 ABI. It also removes the nacl bits in the
toolchain, and some remaining nacl bits.
Updates #30439
Change-Id: I2475d5bb066d1b474e00e40d95b520e7c2e286e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/200077
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Use the following (suboptimal) script to obtain a list of possible
typos:
#!/usr/bin/env sh
set -x
git ls-files |\
grep -e '\.\(c\|cc\|go\)$' |\
xargs -n 1\
awk\
'/\/\// { gsub(/.*\/\//, ""); print; } /\/\*/, /\*\// { gsub(/.*\/\*/, ""); gsub(/\*\/.*/, ""); }' |\
hunspell -d en_US -l |\
grep '^[[:upper:]]\{0,1\}[[:lower:]]\{1,\}$' |\
grep -v -e '^.\{1,4\}$' -e '^.\{16,\}$' |\
sort -f |\
uniq -c |\
awk '$1 == 1 { print $2; }'
Then, go through the results manually and fix the most obvious typos in
the non-vendored code.
Change-Id: I3cb5830a176850e1a0584b8a40b47bde7b260eae
Reviewed-on: https://go-review.googlesource.com/c/go/+/193848
Reviewed-by: Robert Griesemer <gri@golang.org>
math/big.Int Cmp method does not have a fast path for the case if x and y are the same.
Fixes#30856
Change-Id: Ia9a5b5f72db9d73af1b13ed6ac39ecff87d10393
Reviewed-on: https://go-review.googlesource.com/c/go/+/178957
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Shorten some of the longest tests that run during all.bash.
Removes 7r 50u 21s from all.bash.
After this change, all.bash is under 5 minutes again on my laptop.
For #26473.
Change-Id: Ie0460aa935808d65460408feaed210fbaa1d5d79
Reviewed-on: https://go-review.googlesource.com/c/go/+/177559
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For the case where the addresses of parameter z and x of the function
shlVU overlap and the address of z is greater than x, x (input value)
can be polluted during the calculation when the high words of x are
overlapped with the low words of z (output value).
Fixes#31084
Change-Id: I9bb0266a1d7856b8faa9a9b1975d6f57dece0479
Reviewed-on: https://go-review.googlesource.com/c/go/+/169780
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Int.String had no documentation and the documentation for Int.Text
did not mention the handling of the nil pointer case.
Change-Id: I9f21921e431c948545b7cabc7829e4b4e574bbe9
Reviewed-on: https://go-review.googlesource.com/c/go/+/175118
Reviewed-by: Robert Griesemer <gri@golang.org>
Rearranged code slightly to make lifetime of underlying array of
pow5 more explicit in code.
Fixes#31184.
Change-Id: I063081f0e54097c499988d268a23813746592654
Reviewed-on: https://go-review.googlesource.com/c/go/+/170641
Reviewed-by: Filippo Valsorda <filippo@golang.org>
If x does not have an inverse modulo m, and a negative exponent is used,
return nil just like ModInverse does now.
Change-Id: I8fa72f7a851e8cf77c5fab529ede88408740626f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170757
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This addresses the failures we have seen in #31084. The correct
fix is to find the actual bug in the assembly code.
Updates #31084.
Change-Id: I437780c53d0c4423d742e2e3b650b899ce845372
Reviewed-on: https://go-review.googlesource.com/c/go/+/169721
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Implemented via the underlying Int.SetUint64.
Added tests for Rat.SetInt64 and Rat.SetUint64.
Fixes#29579
Change-Id: I03faaffc93e36873b202b58ae72b139dea5c40f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/160682
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This fixes an old oversight. Rat.SetString already permitted
fractions a/b where both a and b could independently specify
a base prefix. With this CL, it now also accepts non-decimal
floating-point numbers.
Fixes#29799.
Change-Id: I9cc65666a5cebb00f0202da2e4fc5654a02e3234
Reviewed-on: https://go-review.googlesource.com/c/go/+/168237
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
The primary change is in nat.scan which now accepts underscores for base 0.
While at it, streamlined error handling in that function as well.
Also, improved the corresponding test significantly by checking the
expected result values also in case of scan errors.
The second major change is in scanExponent which now accepts underscores when
the new sepOk argument is set. While at it, essentially rewrote that
function to match error and underscore handling of nat.scan more closely.
Added a new test for scanExponent which until now was only tested
indirectly.
Finally, updated the documentation for several functions and added many
new test cases to clients of nat.scan.
A major portion of this CL is due to much better test coverage.
Updates #28493.
Change-Id: I7f17b361b633fbe6c798619d891bd5e0a045b5c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/166157
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
In the normal case, only a few words have to be updated when adding a word to a vector.
When that happens, we can simply copy the rest of the words, which is much faster.
However, the overhead of that makes it prohibitive for small vectors,
so we check the size at the beginning.
The implementation is a bit weird to allow addVW to continued to be inlined; see #30548.
The AddVW benchmarks are surprising, but fully repeatable.
The SubVW benchmarks are more or less as expected.
I expect that removing the indirect function call will
help both and make them a bit more normal.
name old time/op new time/op delta
AddVW/1-8 4.27ns ± 2% 3.81ns ± 3% -10.83% (p=0.000 n=89+90)
AddVW/2-8 4.91ns ± 2% 4.34ns ± 1% -11.60% (p=0.000 n=83+90)
AddVW/3-8 5.77ns ± 4% 5.76ns ± 2% ~ (p=0.365 n=91+87)
AddVW/4-8 6.03ns ± 1% 6.03ns ± 1% ~ (p=0.392 n=80+76)
AddVW/5-8 6.48ns ± 2% 6.63ns ± 1% +2.27% (p=0.000 n=76+74)
AddVW/10-8 9.56ns ± 2% 9.56ns ± 1% -0.02% (p=0.002 n=69+76)
AddVW/100-8 90.6ns ± 0% 18.1ns ± 4% -79.99% (p=0.000 n=72+94)
AddVW/1000-8 865ns ± 0% 85ns ± 6% -90.14% (p=0.000 n=66+96)
AddVW/10000-8 8.57µs ± 2% 1.82µs ± 3% -78.73% (p=0.000 n=99+94)
AddVW/100000-8 84.4µs ± 2% 31.8µs ± 4% -62.29% (p=0.000 n=93+98)
name old time/op new time/op delta
SubVW/1-8 3.90ns ± 2% 4.13ns ± 4% +6.02% (p=0.000 n=92+95)
SubVW/2-8 4.15ns ± 1% 5.20ns ± 1% +25.22% (p=0.000 n=83+85)
SubVW/3-8 5.50ns ± 2% 6.22ns ± 6% +13.21% (p=0.000 n=91+97)
SubVW/4-8 5.99ns ± 1% 6.63ns ± 1% +10.63% (p=0.000 n=79+61)
SubVW/5-8 6.75ns ± 4% 6.88ns ± 2% +1.82% (p=0.000 n=98+73)
SubVW/10-8 9.57ns ± 1% 9.56ns ± 1% -0.13% (p=0.000 n=77+64)
SubVW/100-8 90.3ns ± 1% 18.1ns ± 2% -80.00% (p=0.000 n=75+94)
SubVW/1000-8 860ns ± 4% 85ns ± 7% -90.14% (p=0.000 n=97+99)
SubVW/10000-8 8.51µs ± 3% 1.77µs ± 6% -79.21% (p=0.000 n=100+97)
SubVW/100000-8 84.4µs ± 3% 31.5µs ± 3% -62.66% (p=0.000 n=92+92)
Change-Id: I721d7031d40f245b4a284f5bdd93e7bb85e7e937
Reviewed-on: https://go-review.googlesource.com/c/go/+/164968
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>