xref: /dflybsd-src/contrib/openbsd_libm/src/s_modff.c (revision 4382f29d99a100bd77a81697c2f699c11f6a472a)
1*05a0b428SJohn Marino /* s_modff.c -- float version of s_modf.c.
2*05a0b428SJohn Marino  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3*05a0b428SJohn Marino  */
4*05a0b428SJohn Marino 
5*05a0b428SJohn Marino /*
6*05a0b428SJohn Marino  * ====================================================
7*05a0b428SJohn Marino  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*05a0b428SJohn Marino  *
9*05a0b428SJohn Marino  * Developed at SunPro, a Sun Microsystems, Inc. business.
10*05a0b428SJohn Marino  * Permission to use, copy, modify, and distribute this
11*05a0b428SJohn Marino  * software is freely granted, provided that this notice
12*05a0b428SJohn Marino  * is preserved.
13*05a0b428SJohn Marino  * ====================================================
14*05a0b428SJohn Marino  */
15*05a0b428SJohn Marino 
16*05a0b428SJohn Marino #include "math.h"
17*05a0b428SJohn Marino #include "math_private.h"
18*05a0b428SJohn Marino 
19*05a0b428SJohn Marino static const float one = 1.0;
20*05a0b428SJohn Marino 
21*05a0b428SJohn Marino float
modff(float x,float * iptr)22*05a0b428SJohn Marino modff(float x, float *iptr)
23*05a0b428SJohn Marino {
24*05a0b428SJohn Marino 	int32_t i0,jj0;
25*05a0b428SJohn Marino 	u_int32_t i;
26*05a0b428SJohn Marino 	GET_FLOAT_WORD(i0,x);
27*05a0b428SJohn Marino 	jj0 = ((i0>>23)&0xff)-0x7f;	/* exponent of x */
28*05a0b428SJohn Marino 	if(jj0<23) {			/* integer part in x */
29*05a0b428SJohn Marino 	    if(jj0<0) {			/* |x|<1 */
30*05a0b428SJohn Marino 	        SET_FLOAT_WORD(*iptr,i0&0x80000000);	/* *iptr = +-0 */
31*05a0b428SJohn Marino 		return x;
32*05a0b428SJohn Marino 	    } else {
33*05a0b428SJohn Marino 		i = (0x007fffff)>>jj0;
34*05a0b428SJohn Marino 		if((i0&i)==0) {			/* x is integral */
35*05a0b428SJohn Marino 		    u_int32_t ix;
36*05a0b428SJohn Marino 		    *iptr = x;
37*05a0b428SJohn Marino 		    GET_FLOAT_WORD(ix,x);
38*05a0b428SJohn Marino 		    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
39*05a0b428SJohn Marino 		    return x;
40*05a0b428SJohn Marino 		} else {
41*05a0b428SJohn Marino 		    SET_FLOAT_WORD(*iptr,i0&(~i));
42*05a0b428SJohn Marino 		    return x - *iptr;
43*05a0b428SJohn Marino 		}
44*05a0b428SJohn Marino 	    }
45*05a0b428SJohn Marino 	} else {			/* no fraction part */
46*05a0b428SJohn Marino 	    u_int32_t ix;
47*05a0b428SJohn Marino 	    *iptr = x*one;
48*05a0b428SJohn Marino 	    GET_FLOAT_WORD(ix,x);
49*05a0b428SJohn Marino 	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
50*05a0b428SJohn Marino 	    return x;
51*05a0b428SJohn Marino 	}
52*05a0b428SJohn Marino }
53