gitee.com/quant1x/num@v0.3.2/math32/frexp.go (about)

     1  package math32
     2  
     3  // Frexp breaks f into a normalized fraction
     4  // and an integral power of two.
     5  // It returns frac and exp satisfying f == frac × 2**exp,
     6  // with the absolute value of frac in the interval [½, 1).
     7  //
     8  // Special cases are:
     9  //
    10  //	Frexp(±0) = ±0, 0
    11  //	Frexp(±Inf) = ±Inf, 0
    12  //	Frexp(NaN) = NaN, 0
    13  func Frexp(f float32) (frac float32, exp int) {
    14  	return frexp(f)
    15  }
    16  
    17  func frexp(f float32) (frac float32, exp int) {
    18  	// special cases
    19  	switch {
    20  	case f == 0:
    21  		return f, 0 // correctly return -0
    22  	case IsInf(f, 0) || IsNaN(f):
    23  		return f, 0
    24  	}
    25  	f, exp = normalize(f)
    26  	x := Float32bits(f)
    27  	exp += int((x>>shift)&mask) - bias + 1
    28  	x &^= mask << shift
    29  	x |= (-1 + bias) << shift
    30  	frac = Float32frombits(x)
    31  	return
    32  }