s_modff.c revision 97413 
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[] = "$FreeBSD: head/lib/msun/src/s_modff.c 97413 2002-05-28 18:15:04Z alfred $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23static const float one = 1.0;
24
25float
26modff(float x, float *iptr)
27{
28	int32_t i0,j0;
29	u_int32_t i;
30	GET_FLOAT_WORD(i0,x);
31	j0 = ((i0>>23)&0xff)-0x7f;	/* exponent of x */
32	if(j0<23) {			/* integer part in x */
33	    if(j0<0) {			/* |x|<1 */
34	        SET_FLOAT_WORD(*iptr,i0&0x80000000);	/* *iptr = +-0 */
35		return x;
36	    } else {
37		i = (0x007fffff)>>j0;
38		if((i0&i)==0) {			/* x is integral */
39		    u_int32_t ix;
40		    *iptr = x;
41		    GET_FLOAT_WORD(ix,x);
42		    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
43		    return x;
44		} else {
45		    SET_FLOAT_WORD(*iptr,i0&(~i));
46		    return x - *iptr;
47		}
48	    }
49	} else {			/* no fraction part */
50	    u_int32_t ix;
51	    *iptr = x*one;
52	    GET_FLOAT_WORD(ix,x);
53	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
54	    return x;
55	}
56}
57