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-rw-r--r--src/pkg/runtime/complex.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/src/pkg/runtime/complex.c b/src/pkg/runtime/complex.c
new file mode 100644
index 000000000..eeb943940
--- /dev/null
+++ b/src/pkg/runtime/complex.c
@@ -0,0 +1,60 @@
+// 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.
+
+#include "runtime.h"
+
+typedef struct Complex128 Complex128;
+
+void
+runtime·complex128div(Complex128 n, Complex128 d, Complex128 q)
+{
+ int32 ninf, dinf, nnan, dnan;
+ float64 a, b, ratio, denom;
+
+ // Special cases as in C99.
+ ninf = runtime·isInf(n.real, 0) || runtime·isInf(n.imag, 0);
+ dinf = runtime·isInf(d.real, 0) || runtime·isInf(d.imag, 0);
+
+ nnan = !ninf && (runtime·isNaN(n.real) || runtime·isNaN(n.imag));
+ dnan = !dinf && (runtime·isNaN(d.real) || runtime·isNaN(d.imag));
+
+ if(nnan || dnan) {
+ q.real = runtime·NaN();
+ q.imag = runtime·NaN();
+ } else if(ninf && !dinf && !dnan) {
+ q.real = runtime·Inf(0);
+ q.imag = runtime·Inf(0);
+ } else if(!ninf && !nnan && 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·Inf(0);
+ q.imag = runtime·Inf(0);
+ }
+ } 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;
+ }
+ }
+ FLUSH(&q);
+}