xref: /freebsd/lib/msun/src/e_remainderf.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
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 "math.h"
17 #include "math_private.h"
18 
19 static const float zero = 0.0;
20 
21 
22 float
23 remainderf(float x, float p)
24 {
25 	int32_t hx,hp;
26 	u_int32_t sx;
27 	float p_half;
28 
29 	GET_FLOAT_WORD(hx,x);
30 	GET_FLOAT_WORD(hp,p);
31 	sx = hx&0x80000000;
32 	hp &= 0x7fffffff;
33 	hx &= 0x7fffffff;
34 
35     /* purge off exception values */
36 	if((hp==0)||			 	/* p = 0 */
37 	  (hx>=0x7f800000)||			/* x not finite */
38 	  ((hp>0x7f800000)))			/* p is NaN */
39 	    return nan_mix_op(x, p, *)/nan_mix_op(x, p, *);
40 
41 
42 	if (hp<=0x7effffff) x = fmodf(x,p+p);	/* now x < 2p */
43 	if ((hx-hp)==0) return zero*x;
44 	x  = fabsf(x);
45 	p  = fabsf(p);
46 	if (hp<0x01000000) {
47 	    if(x+x>p) {
48 		x-=p;
49 		if(x+x>=p) x -= p;
50 	    }
51 	} else {
52 	    p_half = (float)0.5*p;
53 	    if(x>p_half) {
54 		x-=p;
55 		if(x>=p_half) x -= p;
56 	    }
57 	}
58 	GET_FLOAT_WORD(hx,x);
59 	if ((hx&0x7fffffff)==0) hx = 0;
60 	SET_FLOAT_WORD(x,hx^sx);
61 	return x;
62 }
63