xref: /freebsd/lib/msun/src/s_frexpf.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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 #include "math.h"
18 #include "math_private.h"
19 
20 static const float
21 two25 =  3.3554432000e+07; /* 0x4c000000 */
22 
23 float
24 frexpf(float x, int *eptr)
25 {
26 	int32_t hx,ix;
27 	GET_FLOAT_WORD(hx,x);
28 	ix = 0x7fffffff&hx;
29 	*eptr = 0;
30 	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
31 	if (ix<0x00800000) {		/* subnormal */
32 	    x *= two25;
33 	    GET_FLOAT_WORD(hx,x);
34 	    ix = hx&0x7fffffff;
35 	    *eptr = -25;
36 	}
37 	*eptr += (ix>>23)-126;
38 	hx = (hx&0x807fffff)|0x3f000000;
39 	SET_FLOAT_WORD(x,hx);
40 	return x;
41 }
42