SVN=114204

src/lib/math/fmod.go

@@ -0,0 +1,48 @@
+// Copyright 2009 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 fmod
+
+import	sys "sys"
+export	fmod
+
+/*
+	floating-point mod func without infinity or NaN checking
+ */
+
+func
+fmod(x, y double) double
+{
+	var yexp, rexp int;
+	var r, yfr, rfr double;
+	var sign bool;
+
+	if y == 0 {
+		return x;
+	}
+	if y < 0 {
+		y = -y;
+	}
+
+	yexp,yfr = sys.frexp(y);
+	sign = false;
+	if x < 0 {
+		r = -x;
+		sign = true;
+	} else {
+		r = x;
+	}
+
+	for r >= y {
+		rexp,rfr = sys.frexp(r);
+		if rfr < yfr {
+			rexp = rexp - 1;
+		}
+		r = r - sys.ldexp(y, rexp-yexp);
+	}
+	if sign {
+		r = -r;
+	}
+	return r;
+}