xref: /freebsd/lib/msun/src/e_remainderf.c (revision 97549c34ecaf74580941fdc9c5bd1050e4b1f6ce)
1 /* e_remainderf.c -- float version of e_remainder.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 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
18 
19 #include "math.h"
20 #include "math_private.h"
21 
22 static const float zero = 0.0;
23 
24 
25 float
26 __ieee754_remainderf(float x, float p)
27 {
28 	int32_t hx,hp;
29 	u_int32_t sx;
30 	float p_half;
31 
32 	GET_FLOAT_WORD(hx,x);
33 	GET_FLOAT_WORD(hp,p);
34 	sx = hx&0x80000000;
35 	hp &= 0x7fffffff;
36 	hx &= 0x7fffffff;
37 
38     /* purge off exception values */
39 	if(hp==0) return (x*p)/(x*p);	 	/* p = 0 */
40 	if((hx>=0x7f800000)||			/* x not finite */
41 	  ((hp>0x7f800000)))			/* p is NaN */
42 	    return ((long double)x*p)/((long double)x*p);
43 
44 
45 	if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p);	/* now x < 2p */
46 	if ((hx-hp)==0) return zero*x;
47 	x  = fabsf(x);
48 	p  = fabsf(p);
49 	if (hp<0x01000000) {
50 	    if(x+x>p) {
51 		x-=p;
52 		if(x+x>=p) x -= p;
53 	    }
54 	} else {
55 	    p_half = (float)0.5*p;
56 	    if(x>p_half) {
57 		x-=p;
58 		if(x>=p_half) x -= p;
59 	    }
60 	}
61 	GET_FLOAT_WORD(hx,x);
62 	if ((hx&0x7fffffff)==0) hx = 0;
63 	SET_FLOAT_WORD(x,hx^sx);
64 	return x;
65 }
66