xref: /freebsd/lib/msun/src/s_frexpf.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
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 <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include "math.h"
20 #include "math_private.h"
21 
22 static const float
23 two25 =  3.3554432000e+07; /* 0x4c000000 */
24 
25 float
26 frexpf(float x, int *eptr)
27 {
28 	int32_t hx,ix;
29 	GET_FLOAT_WORD(hx,x);
30 	ix = 0x7fffffff&hx;
31 	*eptr = 0;
32 	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
33 	if (ix<0x00800000) {		/* subnormal */
34 	    x *= two25;
35 	    GET_FLOAT_WORD(hx,x);
36 	    ix = hx&0x7fffffff;
37 	    *eptr = -25;
38 	}
39 	*eptr += (ix>>23)-126;
40 	hx = (hx&0x807fffff)|0x3f000000;
41 	SET_FLOAT_WORD(x,hx);
42 	return x;
43 }
44