s_modff.c revision 2117 
1/* s_modff.c -- float version of s_modf.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
17static char rcsid[] = "$Id: s_modff.c,v 1.2 1994/08/18 23:07:12 jtc Exp $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23#ifdef __STDC__
24static const float one = 1.0;
25#else
26static float one = 1.0;
27#endif
28
29#ifdef __STDC__
30	float modff(float x, float *iptr)
31#else
32	float modff(x, iptr)
33	float x,*iptr;
34#endif
35{
36	int32_t i0,j0;
37	u_int32_t i;
38	GET_FLOAT_WORD(i0,x);
39	j0 = ((i0>>23)&0xff)-0x7f;	/* exponent of x */
40	if(j0<23) {			/* integer part in x */
41	    if(j0<0) {			/* |x|<1 */
42	        SET_FLOAT_WORD(*iptr,i0&0x80000000);	/* *iptr = +-0 */
43		return x;
44	    } else {
45		i = (0x007fffff)>>j0;
46		if((i0&i)==0) {			/* x is integral */
47		    u_int32_t ix;
48		    *iptr = x;
49		    GET_FLOAT_WORD(ix,x);
50		    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
51		    return x;
52		} else {
53		    SET_FLOAT_WORD(*iptr,i0&(~i));
54		    return x - *iptr;
55		}
56	    }
57	} else {			/* no fraction part */
58	    u_int32_t ix;
59	    *iptr = x*one;
60	    GET_FLOAT_WORD(ix,x);
61	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
62	    return x;
63	}
64}
65