1 /* @(#)s_nextafter.c 5.1 93/09/24 */
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
10 * ====================================================
13 #if defined(LIBM_SCCS) && !defined(lint)
14 static char rcsid[] = "$NetBSD: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp $";
19 * return the next machine floating-point number of x in the
25 #include "math_private.h"
28 double nextafter(double x, double y)
37 EXTRACT_WORDS(hx,lx,x);
38 EXTRACT_WORDS(hy,ly,y);
39 ix = hx&0x7fffffff; /* |x| */
40 iy = hy&0x7fffffff; /* |y| */
42 if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
43 ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */
45 if(x==y) return x; /* x=y, return x */
46 if((ix|lx)==0) { /* x == 0 */
47 INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */
49 if(y==x) return y; else return x; /* raise underflow flag */
51 if(hx>=0) { /* x > 0 */
52 if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */
55 } else { /* x < y, x += ulp */
60 if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
63 } else { /* x > y, x += ulp */
69 if(hy>=0x7ff00000) return x+x; /* overflow */
70 if(hy<0x00100000) { /* underflow */
72 if(y!=x) { /* raise underflow flag */
73 INSERT_WORDS(y,hx,lx);
77 INSERT_WORDS(x,hx,lx);