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package math32
// 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 Frexp(f float32) (frac float32, exp int) {
return frexp(f)
}
func frexp(f float32) (frac float32, exp int) {
// special cases
switch {
case f == 0:
return f, 0 // correctly return -0
case IsInf(f, 0) || IsNaN(f):
return f, 0
}
f, exp = normalize(f)
x := Float32bits(f)
exp += int((x>>shift)&mask) - bias + 1
x &^= mask << shift
x |= (-1 + bias) << shift
frac = Float32frombits(x)
return
}
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