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author | Tianon Gravi <admwiggin@gmail.com> | 2015-01-15 12:50:40 -0700 |
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committer | Tianon Gravi <admwiggin@gmail.com> | 2015-01-15 12:50:40 -0700 |
commit | 2a0db60599fdd75b1bc3e297180fbe1282763759 (patch) | |
tree | 68d43c3e30d9ab961ddf6b7365201ca6b675b253 /src/math/mod.go | |
parent | ef33cba3c8de6c431df56503df51fcd3a473c89e (diff) | |
parent | f154da9e12608589e8d5f0508f908a0c3e88a1bb (diff) | |
download | golang-2a0db60599fdd75b1bc3e297180fbe1282763759.tar.gz |
Merge tag 'upstream/1.4' into debian-experimental
* tag 'upstream/1.4':
Imported Upstream version 1.4
Diffstat (limited to 'src/math/mod.go')
-rw-r--r-- | src/math/mod.go | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/math/mod.go b/src/math/mod.go new file mode 100644 index 000000000..e1a414e5f --- /dev/null +++ b/src/math/mod.go @@ -0,0 +1,50 @@ +// 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. +*/ + +// Mod 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: +// Mod(±Inf, y) = NaN +// Mod(NaN, y) = NaN +// Mod(x, 0) = NaN +// Mod(x, ±Inf) = x +// Mod(x, NaN) = NaN +func Mod(x, y float64) float64 + +func mod(x, y float64) float64 { + if 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 +} |