| // 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 |
| |
| // Abs returns the absolute value of x. |
| // |
| // Special cases are: |
| // Abs(±Inf) = +Inf |
| // Abs(NaN) = NaN |
| |
| //extern fabs |
| func libc_fabs(float64) float64 |
| |
| func Abs(x float64) float64 { |
| return libc_fabs(x) |
| } |
| |
| func abs(x float64) float64 { |
| // TODO: once golang.org/issue/13095 is fixed, change this to: |
| // return Float64frombits(Float64bits(x) &^ (1 << 63)) |
| // But for now, this generates better code and can also be inlined: |
| if x < 0 { |
| return -x |
| } |
| if x == 0 { |
| return 0 // return correctly abs(-0) |
| } |
| return x |
| } |
