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
Frexp breaks f into a normalized fraction and an integral power of two. It returns frac and exp satisfying f == frac × 2**exp, with the absolute value of frac in the interval [½, 1). Special cases are: Frexp(±0) = ±0, 0 Frexp(±Inf) = ±Inf, 0 Frexp(NaN) = NaN, 0
func ( float64) ( float64,  int)
special cases
	switch {
	case  == 0:
		return , 0 // correctly return -0
	case IsInf(, 0) || IsNaN():
		return , 0
	}
	,  = normalize()
	 := Float64bits()
	 += int((>>shift)&mask) - bias + 1
	 &^= mask << shift
	 |= (-1 + bias) << shift
	 = Float64frombits()
	return