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runtime: convert complex128div to go. 

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/116320043
This commit is contained in:
Keith Randall 2014-07-25 15:12:45 -07:00
parent da8f677815
commit c403af83a6
2 changed files with 52 additions and 58 deletions
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52
src/pkg/runtime/complex.go Normal file
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@ -0,0 +1,52 @@
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
func complex128div(n complex128, d complex128) complex128 {
// Special cases as in C99.
ninf := real(n) == posinf || real(n) == neginf ||
imag(n) == posinf || imag(n) == neginf
dinf := real(d) == posinf || real(d) == neginf ||
imag(d) == posinf || imag(d) == neginf
nnan := !ninf && (real(n) != real(n) || imag(n) != imag(n))
dnan := !dinf && (real(d) != real(d) || imag(d) != imag(d))
switch {
case nnan || dnan:
return complex(nan, nan)
case ninf && !dinf:
return complex(posinf, posinf)
case !ninf && dinf:
return complex(0, 0)
case real(d) == 0 && imag(d) == 0:
if real(n) == 0 && imag(n) == 0 {
return complex(nan, nan)
} else {
return complex(posinf, posinf)
}
default:
// Standard complex arithmetic, factored to avoid unnecessary overflow.
a := real(d)
if a < 0 {
a = -a
}
b := imag(d)
if b < 0 {
b = -b
}
if a <= b {
ratio := real(d) / imag(d)
denom := real(d)*ratio + imag(d)
return complex((real(n)*ratio+imag(n))/denom,
(imag(n)*ratio-real(n))/denom)
} else {
ratio := imag(d) / real(d)
denom := imag(d)*ratio + real(d)
return complex((imag(n)*ratio+real(n))/denom,
(imag(n)-real(n)*ratio)/denom)
}
}
}

58
src/pkg/runtime/complex.goc
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@ -1,58 +0,0 @@
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
#include "runtime.h"
func complex128div(n Complex128, d Complex128) (q Complex128) {
int32 ninf, dinf, nnan, dnan;
float64 a, b, ratio, denom;
// Special cases as in C99.
ninf = n.real == runtime·posinf || n.real == runtime·neginf ||
n.imag == runtime·posinf || n.imag == runtime·neginf;
dinf = d.real == runtime·posinf || d.real == runtime·neginf ||
d.imag == runtime·posinf || d.imag == runtime·neginf;
nnan = !ninf && (ISNAN(n.real) || ISNAN(n.imag));
dnan = !dinf && (ISNAN(d.real) || ISNAN(d.imag));
if(nnan || dnan) {
q.real = runtime·nan;
q.imag = runtime·nan;
} else if(ninf && !dinf) {
q.real = runtime·posinf;
q.imag = runtime·posinf;
} else if(!ninf && dinf) {
q.real = 0;
q.imag = 0;
} else if(d.real == 0 && d.imag == 0) {
if(n.real == 0 && n.imag == 0) {
q.real = runtime·nan;
q.imag = runtime·nan;
} else {
q.real = runtime·posinf;
q.imag = runtime·posinf;
}
} else {
// Standard complex arithmetic, factored to avoid unnecessary overflow.
a = d.real;
if(a < 0)
a = -a;
b = d.imag;
if(b < 0)
b = -b;
if(a <= b) {
ratio = d.real/d.imag;
denom = d.real*ratio + d.imag;
q.real = (n.real*ratio + n.imag) / denom;
q.imag = (n.imag*ratio - n.real) / denom;
} else {
ratio = d.imag/d.real;
denom = d.imag*ratio + d.real;
q.real = (n.imag*ratio + n.real) / denom;
q.imag = (n.imag - n.real*ratio) / denom;
}
}
}