// 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 Frexp(f float64) (frac float64, exp int) func frexp(f float64) (frac float64, 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 := Float64bits(f) exp += int((x>>shift)&mask) - bias + 1 x &^= mask << shift x |= (-1 + bias) << shift frac = Float64frombits(x) return }