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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/math/fmod.go
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Diffstat (limited to 'libgo/go/math/fmod.go')
-rw-r--r--libgo/go/math/fmod.go48
1 files changed, 48 insertions, 0 deletions
diff --git a/libgo/go/math/fmod.go b/libgo/go/math/fmod.go
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+// Copyright 2009-2010 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.
+
+package math
+
+
+/*
+ Floating-point mod function.
+*/
+
+// Fmod returns the floating-point remainder of x/y.
+// The magnitude of the result is less than y and its
+// sign agrees with that of x.
+//
+// Special cases are:
+// if x is not finite, Fmod returns NaN
+// if y is 0 or NaN, Fmod returns NaN
+func Fmod(x, y float64) float64 {
+ // TODO(rsc): Remove manual inlining of IsNaN, IsInf
+ // when compiler does it for us.
+ if y == 0 || x > MaxFloat64 || x < -MaxFloat64 || x != x || y != y { // y == 0 || IsInf(x, 0) || IsNaN(x) || IsNan(y)
+ return NaN()
+ }
+ 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
+}