From b129670ca135bd6be7b4afcadeb0bcec0675789e Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Tue, 9 Mar 2010 12:49:24 -0800
Subject: 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
---
 src/pkg/runtime/Makefile  |  1 +
 src/pkg/runtime/complex.c | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 src/pkg/runtime/complex.c

(limited to 'src/pkg/runtime')

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);
+}
-- 
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