gcc/libgo/go/math/modf.go
2021-08-12 20:23:07 -07:00

43 lines
910 B
Go

// 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) {
if haveArchModf {
return archModf(f)
}
return modf(f)
}
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
}