xref: /freebsd/lib/msun/src/s_frexpf.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 #ifndef lint
17 static char rcsid[] = "$FreeBSD$";
18 #endif
19 
20 #include "math.h"
21 #include "math_private.h"
22 
23 static const float
24 two25 =  3.3554432000e+07; /* 0x4c000000 */
25 
26 float
27 frexpf(float x, int *eptr)
28 {
29 	int32_t hx,ix;
30 	GET_FLOAT_WORD(hx,x);
31 	ix = 0x7fffffff&hx;
32 	*eptr = 0;
33 	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
34 	if (ix<0x00800000) {		/* subnormal */
35 	    x *= two25;
36 	    GET_FLOAT_WORD(hx,x);
37 	    ix = hx&0x7fffffff;
38 	    *eptr = -25;
39 	}
40 	*eptr += (ix>>23)-126;
41 	hx = (hx&0x807fffff)|0x3f000000;
42 	SET_FLOAT_WORD(x,hx);
43 	return x;
44 }
45