xref: /freebsd/lib/msun/src/s_modff.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
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[] = "$FreeBSD$";
18 #endif
19 
20 #include "math.h"
21 #include "math_private.h"
22 
23 static const float one = 1.0;
24 
25 float
26 modff(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 	    if (x != x)			/* NaN */
53 		return x;
54 	    GET_FLOAT_WORD(ix,x);
55 	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
56 	    return x;
57 	}
58 }
59