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// 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;
}
}
}
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