Source file src/math/modf.go

Documentation: math

		 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  	if haveArchModf {
		15  		return archModf(f)
		16  	}
		17  	return modf(f)
		18  }
		19  
		20  func modf(f float64) (int float64, frac float64) {
		21  	if f < 1 {
		22  		switch {
		23  		case f < 0:
		24  			int, frac = Modf(-f)
		25  			return -int, -frac
		26  		case f == 0:
		27  			return f, f // Return -0, -0 when f == -0
		28  		}
		29  		return 0, f
		30  	}
		31  
		32  	x := Float64bits(f)
		33  	e := uint(x>>shift)&mask - bias
		34  
		35  	// Keep the top 12+e bits, the integer part; clear the rest.
		36  	if e < 64-12 {
		37  		x &^= 1<<(64-12-e) - 1
		38  	}
		39  	int = Float64frombits(x)
		40  	frac = f - int
		41  	return
		42  }
		43  

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