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0157c72d13
Depends on CL 6197045. Result obtained on Core i7 620M, Darwin/amd64: benchmark old ns/op new ns/op delta BenchmarkComplex128DivNormal 57 28 -50.78% BenchmarkComplex128DivNisNaN 49 15 -68.90% BenchmarkComplex128DivDisNaN 49 15 -67.88% BenchmarkComplex128DivNisInf 40 12 -68.50% BenchmarkComplex128DivDisInf 33 13 -61.06% Result obtained on Core i7 620M, Darwin/386: benchmark old ns/op new ns/op delta BenchmarkComplex128DivNormal 89 50 -44.05% BenchmarkComplex128DivNisNaN 307 802 +161.24% BenchmarkComplex128DivDisNaN 309 788 +155.02% BenchmarkComplex128DivNisInf 278 237 -14.75% BenchmarkComplex128DivDisInf 46 22 -52.46% Result obtained on 700MHz OMAP4460, Linux/ARM: benchmark old ns/op new ns/op delta BenchmarkComplex128DivNormal 1557 465 -70.13% BenchmarkComplex128DivNisNaN 1443 220 -84.75% BenchmarkComplex128DivDisNaN 1481 218 -85.28% BenchmarkComplex128DivNisInf 952 216 -77.31% BenchmarkComplex128DivDisInf 861 231 -73.17% The 386 version has a performance regression, but as we have decided to use SSE2 instead of x87 FPU for 386 too (issue 3912), I won't address this issue. R=dsymonds, mchaten, iant, dave, mtj, rsc, r CC=golang-dev https://golang.org/cl/6024045
63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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typedef struct Complex128 Complex128;
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void
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runtime·complex128div(Complex128 n, Complex128 d, Complex128 q)
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{
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int32 ninf, dinf, nnan, dnan;
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float64 a, b, ratio, denom;
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// Special cases as in C99.
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ninf = n.real == runtime·posinf || n.real == runtime·neginf ||
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n.imag == runtime·posinf || n.imag == runtime·neginf;
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dinf = d.real == runtime·posinf || d.real == runtime·neginf ||
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d.imag == runtime·posinf || d.imag == runtime·neginf;
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nnan = !ninf && (ISNAN(n.real) || ISNAN(n.imag));
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dnan = !dinf && (ISNAN(d.real) || ISNAN(d.imag));
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if(nnan || dnan) {
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q.real = runtime·nan;
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q.imag = runtime·nan;
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} else if(ninf && !dinf) {
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q.real = runtime·posinf;
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q.imag = runtime·posinf;
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} else if(!ninf && dinf) {
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q.real = 0;
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q.imag = 0;
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} else if(d.real == 0 && d.imag == 0) {
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if(n.real == 0 && n.imag == 0) {
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q.real = runtime·nan;
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q.imag = runtime·nan;
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} else {
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q.real = runtime·posinf;
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q.imag = runtime·posinf;
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}
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} else {
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// Standard complex arithmetic, factored to avoid unnecessary overflow.
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a = d.real;
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if(a < 0)
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a = -a;
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b = d.imag;
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if(b < 0)
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b = -b;
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if(a <= b) {
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ratio = d.real/d.imag;
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denom = d.real*ratio + d.imag;
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q.real = (n.real*ratio + n.imag) / denom;
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q.imag = (n.imag*ratio - n.real) / denom;
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} else {
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ratio = d.imag/d.real;
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denom = d.imag*ratio + d.real;
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q.real = (n.imag*ratio + n.real) / denom;
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q.imag = (n.imag - n.real*ratio) / denom;
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}
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}
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FLUSH(&q);
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}
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