xref: /freebsd/lib/msun/src/e_remainderf.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 #ifndef lint
17 static char rcsid[] = "$FreeBSD$";
18 #endif
19 
20 #include "math.h"
21 #include "math_private.h"
22 
23 static const float zero = 0.0;
24 
25 
26 float
27 __ieee754_remainderf(float x, float p)
28 {
29 	int32_t hx,hp;
30 	u_int32_t sx;
31 	float p_half;
32 
33 	GET_FLOAT_WORD(hx,x);
34 	GET_FLOAT_WORD(hp,p);
35 	sx = hx&0x80000000;
36 	hp &= 0x7fffffff;
37 	hx &= 0x7fffffff;
38 
39     /* purge off exception values */
40 	if(hp==0) return (x*p)/(x*p);	 	/* p = 0 */
41 	if((hx>=0x7f800000)||			/* x not finite */
42 	  ((hp>0x7f800000)))			/* p is NaN */
43 	    return (x*p)/(x*p);
44 
45 
46 	if (hp<=0x7effffff) x = __ieee754_fmodf(x,p+p);	/* now x < 2p */
47 	if ((hx-hp)==0) return zero*x;
48 	x  = fabsf(x);
49 	p  = fabsf(p);
50 	if (hp<0x01000000) {
51 	    if(x+x>p) {
52 		x-=p;
53 		if(x+x>=p) x -= p;
54 	    }
55 	} else {
56 	    p_half = (float)0.5*p;
57 	    if(x>p_half) {
58 		x-=p;
59 		if(x>=p_half) x -= p;
60 	    }
61 	}
62 	GET_FLOAT_WORD(hx,x);
63 	SET_FLOAT_WORD(x,hx^sx);
64 	return x;
65 }
66