xref: /freebsd/lib/msun/src/s_modff.c (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
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
17 static 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__
24 static const float one = 1.0;
25 #else
26 static 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