1 files changed, 58 insertions, 0 deletions
diff --git a/src/pkg/runtime/complex.goc b/src/pkg/runtime/complex.goc
new file mode 100644
index 000000000..40935cf1c
--- /dev/null
+++ b/src/pkg/runtime/complex.goc
@@ -0,0 +1,58 @@
+// 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;
+		}
+	}
+}