github.com/huandu/go@v0.0.0-20151114150818-04e615e41150/src/math/modf.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package math
     6  
     7  // Modf returns integer and fractional floating-point numbers
     8  // that sum to f.  Both values have the same sign as f.
     9  //
    10  // Special cases are:
    11  //	Modf(±Inf) = ±Inf, NaN
    12  //	Modf(NaN) = NaN, NaN
    13  func Modf(f float64) (int float64, frac float64)
    14  
    15  func modf(f float64) (int float64, frac float64) {
    16  	if f < 1 {
    17  		if f < 0 {
    18  			int, frac = Modf(-f)
    19  			return -int, -frac
    20  		}
    21  		return 0, f
    22  	}
    23  
    24  	x := Float64bits(f)
    25  	e := uint(x>>shift)&mask - bias
    26  
    27  	// Keep the top 12+e bits, the integer part; clear the rest.
    28  	if e < 64-12 {
    29  		x &^= 1<<(64-12-e) - 1
    30  	}
    31  	int = Float64frombits(x)
    32  	frac = f - int
    33  	return
    34  }