Retro68/gcc/libgo/go/math/nextafter.go
Wolfgang Thaller aaf905ce07 add gcc 4.70
2012-03-28 01:13:14 +02:00

28 lines
682 B
Go

// Copyright 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
// Nextafter returns the next representable value after x towards y.
// If x == y, then x is returned.
//
// Special cases are:
// Nextafter(NaN, y) = NaN
// Nextafter(x, NaN) = NaN
func Nextafter(x, y float64) (r float64) {
switch {
case IsNaN(x) || IsNaN(y): // special case
r = NaN()
case x == y:
r = x
case x == 0:
r = Copysign(Float64frombits(1), y)
case (y > x) == (x > 0):
r = Float64frombits(Float64bits(x) + 1)
default:
r = Float64frombits(Float64bits(x) - 1)
}
return
}