identical complex implementation

for 6g and 8g. can also be used
for 5g. 5g is still a stub.

R=rsc
CC=golang-dev
http://codereview.appspot.com/362041

2 files changed, 37 insertions, 0 deletions

diff --git a/src/pkg/runtime/Makefile b/src/pkg/runtime/Makefile
index 767472063..103515c13 100644
--- a/src/pkg/runtime/Makefile
+++ b/src/pkg/runtime/Makefile
@@ -48,6 +48,7 @@ OFILES=\
 	chan.$O\
 	closure.$O\
 	float.$O\
+	complex.$O\
 	hashmap.$O\
 	iface.$O\
 	malloc.$O\
diff --git a/src/pkg/runtime/complex.c b/src/pkg/runtime/complex.c
new file mode 100644
index 000000000..72c65467d
--- /dev/null
+++ b/src/pkg/runtime/complex.c
@@ -0,0 +1,36 @@
+// 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"
+
+// complex128div(num, den complex128) (quo complex128)
+void
+·complex128div(float64 numreal, float64 numimag,
+	float64 denreal, float64 denimag,
+	float64 quoreal, float64 quoimag)
+{
+	float64 a, b, ratio, denom;
+
+	a = denreal;
+	if(a < 0)
+		a = -a;
+	b = denimag;
+	if(b < 0)
+		b = -b;
+	if(a <= b) {
+		if(b == 0)
+			throw("complex divide");
+		ratio = denreal/denimag;
+		denom = denreal*ratio + denimag;
+		quoreal = (numreal*ratio + numimag) / denom;
+		quoimag = (numimag*ratio - numreal) / denom;
+	} else {
+		ratio = denimag/denreal;
+		denom = denimag*ratio + denreal;
+		quoreal = (numimag*ratio + numreal) / denom;
+		quoimag = (numimag - numreal*ratio) / denom;
+	}
+	FLUSH(&quoreal);
+	FLUSH(&quoimag);
+}