1 files changed, 41 insertions, 0 deletions
diff --git a/src/pkg/math/fmod.go b/src/pkg/math/fmod.go
new file mode 100644
index 000000000..617f5408b
--- /dev/null
+++ b/src/pkg/math/fmod.go
@@ -0,0 +1,41 @@
+// 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 math
+
+import "math"
+
+/*
+ *	floating-point mod func without infinity or NaN checking
+ */
+
+// Fmod returns the floating-point remainder of x/y.
+func Fmod(x, y float64) float64 {
+	if y == 0 {
+		return x;
+	}
+	if y < 0 {
+		y = -y;
+	}
+
+	yfr, yexp := Frexp(y);
+	sign := false;
+	r := x;
+	if x < 0 {
+		r = -x;
+		sign = true;
+	}
+
+	for r >= y {
+		rfr, rexp := Frexp(r);
+		if rfr < yfr {
+			rexp = rexp - 1;
+		}
+		r = r - Ldexp(y, rexp-yexp);
+	}
+	if sign {
+		r = -r;
+	}
+	return r;
+}