1 files changed, 37 insertions, 0 deletions
diff --git a/src/math/modf.go b/src/math/modf.go
new file mode 100644
index 0000000..c5bb894
--- /dev/null
+++ b/src/math/modf.go
@@ -0,0 +1,37 @@
+// 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
+
+// Modf returns integer and fractional floating-point numbers
+// that sum to f. Both values have the same sign as f.
+//
+// Special cases are:
+//	Modf(±Inf) = ±Inf, NaN
+//	Modf(NaN) = NaN, NaN
+func Modf(f float64) (int float64, frac float64)
+
+func modf(f float64) (int float64, frac float64) {
+	if f < 1 {
+		switch {
+		case f < 0:
+			int, frac = Modf(-f)
+			return -int, -frac
+		case f == 0:
+			return f, f // Return -0, -0 when f == -0
+		}
+		return 0, f
+	}
+
+	x := Float64bits(f)
+	e := uint(x>>shift)&mask - bias
+
+	// Keep the top 12+e bits, the integer part; clear the rest.
+	if e < 64-12 {
+		x &^= 1<<(64-12-e) - 1
+	}
+	int = Float64frombits(x)
+	frac = f - int
+	return
+}