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# Source file src/math/frexp.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  // Frexp breaks f into a normalized fraction
8  // and an integral power of two.
9  // It returns frac and exp satisfying f == frac × 2**exp,
10  // with the absolute value of frac in the interval [½, 1).
11  //
12  // Special cases are:
13  //	Frexp(±0) = ±0, 0
14  //	Frexp(±Inf) = ±Inf, 0
15  //	Frexp(NaN) = NaN, 0
16  func Frexp(f float64) (frac float64, exp int)
17
18  func frexp(f float64) (frac float64, exp int) {
19  	// special cases
20  	switch {
21  	case f == 0:
22  		return f, 0 // correctly return -0
23  	case IsInf(f, 0) || IsNaN(f):
24  		return f, 0
25  	}
26  	f, exp = normalize(f)
27  	x := Float64bits(f)
28  	exp += int((x>>shift)&mask) - bias + 1
29  	x &^= mask << shift
30  	x |= (-1 + bias) << shift
31  	frac = Float64frombits(x)
32  	return
33  }
34
```

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