s_nextafterf.c revision 97409 
1/* s_nextafterf.c -- float version of s_nextafter.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
17static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_nextafterf.c 97409 2002-05-28 17:51:46Z alfred $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23	float nextafterf(float x, float y)
24{
25	int32_t hx,hy,ix,iy;
26
27	GET_FLOAT_WORD(hx,x);
28	GET_FLOAT_WORD(hy,y);
29	ix = hx&0x7fffffff;		/* |x| */
30	iy = hy&0x7fffffff;		/* |y| */
31
32	if((ix>0x7f800000) ||   /* x is nan */
33	   (iy>0x7f800000))     /* y is nan */
34	   return x+y;
35	if(x==y) return x;		/* x=y, return x */
36	if(ix==0) {				/* x == 0 */
37	    SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */
38	    y = x*x;
39	    if(y==x) return y; else return x;	/* raise underflow flag */
40	}
41	if(hx>=0) {				/* x > 0 */
42	    if(hx>hy) {				/* x > y, x -= ulp */
43		hx -= 1;
44	    } else {				/* x < y, x += ulp */
45		hx += 1;
46	    }
47	} else {				/* x < 0 */
48	    if(hy>=0||hx>hy){			/* x < y, x -= ulp */
49		hx -= 1;
50	    } else {				/* x > y, x += ulp */
51		hx += 1;
52	    }
53	}
54	hy = hx&0x7f800000;
55	if(hy>=0x7f800000) return x+x;	/* overflow  */
56	if(hy<0x00800000) {		/* underflow */
57	    y = x*x;
58	    if(y!=x) {		/* raise underflow flag */
59	        SET_FLOAT_WORD(y,hx);
60		return y;
61	    }
62	}
63	SET_FLOAT_WORD(x,hx);
64	return x;
65}
66