xref: /freebsd/lib/msun/src/s_frexpf.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1 /* s_frexpf.c -- float version of s_frexp.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 #include "math.h"
17 #include "math_private.h"
18 
19 static const float
20 two25 =  3.3554432000e+07; /* 0x4c000000 */
21 
22 float
23 frexpf(float x, int *eptr)
24 {
25 	int32_t hx,ix;
26 	GET_FLOAT_WORD(hx,x);
27 	ix = 0x7fffffff&hx;
28 	*eptr = 0;
29 	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
30 	if (ix<0x00800000) {		/* subnormal */
31 	    x *= two25;
32 	    GET_FLOAT_WORD(hx,x);
33 	    ix = hx&0x7fffffff;
34 	    *eptr = -25;
35 	}
36 	*eptr += (ix>>23)-126;
37 	hx = (hx&0x807fffff)|0x3f000000;
38 	SET_FLOAT_WORD(x,hx);
39 	return x;
40 }
41