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);
+}