xref: /minix3/lib/libm/src/s_frexpf.c (revision 2fe8fb192fe7e8720e3e7a77f928da545e872a6a)
1*2fe8fb19SBen Gras /* s_frexpf.c -- float version of s_frexp.c.
2*2fe8fb19SBen Gras  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3*2fe8fb19SBen Gras  */
4*2fe8fb19SBen Gras 
5*2fe8fb19SBen Gras /*
6*2fe8fb19SBen Gras  * ====================================================
7*2fe8fb19SBen Gras  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*2fe8fb19SBen Gras  *
9*2fe8fb19SBen Gras  * Developed at SunPro, a Sun Microsystems, Inc. business.
10*2fe8fb19SBen Gras  * Permission to use, copy, modify, and distribute this
11*2fe8fb19SBen Gras  * software is freely granted, provided that this notice
12*2fe8fb19SBen Gras  * is preserved.
13*2fe8fb19SBen Gras  * ====================================================
14*2fe8fb19SBen Gras  */
15*2fe8fb19SBen Gras 
16*2fe8fb19SBen Gras #include <sys/cdefs.h>
17*2fe8fb19SBen Gras #if defined(LIBM_SCCS) && !defined(lint)
18*2fe8fb19SBen Gras __RCSID("$NetBSD: s_frexpf.c,v 1.10 2007/08/21 20:12:27 drochner Exp $");
19*2fe8fb19SBen Gras #endif
20*2fe8fb19SBen Gras 
21*2fe8fb19SBen Gras #include "math.h"
22*2fe8fb19SBen Gras #include "math_private.h"
23*2fe8fb19SBen Gras 
24*2fe8fb19SBen Gras static const float
25*2fe8fb19SBen Gras two25 =  3.3554432000e+07; /* 0x4c000000 */
26*2fe8fb19SBen Gras 
27*2fe8fb19SBen Gras float
frexpf(float x,int * eptr)28*2fe8fb19SBen Gras frexpf(float x, int *eptr)
29*2fe8fb19SBen Gras {
30*2fe8fb19SBen Gras 	int32_t hx,ix;
31*2fe8fb19SBen Gras 	GET_FLOAT_WORD(hx,x);
32*2fe8fb19SBen Gras 	ix = 0x7fffffff&hx;
33*2fe8fb19SBen Gras 	*eptr = 0;
34*2fe8fb19SBen Gras 	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
35*2fe8fb19SBen Gras 	if (ix<0x00800000) {		/* subnormal */
36*2fe8fb19SBen Gras 	    x *= two25;
37*2fe8fb19SBen Gras 	    GET_FLOAT_WORD(hx,x);
38*2fe8fb19SBen Gras 	    ix = hx&0x7fffffff;
39*2fe8fb19SBen Gras 	    *eptr = -25;
40*2fe8fb19SBen Gras 	}
41*2fe8fb19SBen Gras 	*eptr += (ix>>23)-126;
42*2fe8fb19SBen Gras 	hx = (hx&0x807fffff)|0x3f000000;
43*2fe8fb19SBen Gras 	SET_FLOAT_WORD(x,hx);
44*2fe8fb19SBen Gras 	return x;
45*2fe8fb19SBen Gras }
46