summaryrefslogtreecommitdiff
path: root/sysdeps/libm-ieee754/s_nextafterl.c
blob: 0327261f3384ec8f82c024cfd0ff2d7a13628ec1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
/* s_nextafterl.c -- long double version of s_nextafter.c.
 * Conversion to long double by Ulrich Drepper,
 * Cygnus Support, drepper@cygnus.com.
 */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif

/* IEEE functions
 *	nextafterl(x,y)
 *	return the next machine floating-point number of x in the
 *	direction toward y.
 *   Special cases:
 */

#include "math.h"
#include "math_private.h"

#ifdef __STDC__
	long double __nextafterl(long double x, long double y)
#else
	long double __nextafterl(x,y)
	long double x,y;
#endif
{
	int32_t hx,hy,ix,iy;
	u_int32_t lx,ly,esx,esy;

	GET_LDOUBLE_WORDS(esx,hx,lx,x);
	GET_LDOUBLE_WORDS(esy,hy,ly,y);
	ix = esx&0x7fff;		/* |x| */
	iy = esy&0x7fff;		/* |y| */

	if(((ix==0x7fff)&&((hx|lx)|-(hx|lx))!=0) ||   /* x is nan */
	   ((iy==0x7fff)&&((hy|ly)|-(hy|ly))!=0))     /* y is nan */
	   return x+y;
	if(x==y) return x;		/* x=y, return x */
	if((ix|hx|lx)==0) {			/* x == 0 */
	    SET_LDOUBLE_WORDS(x,esx&0x8000,0,1);/* return +-minsubnormal */
	    y = x*x;
	    if(y==x) return y; else return x;	/* raise underflow flag */
	}
	if(esx<0x8000) {			/* x > 0 */
	    if(ix>iy||((ix==iy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
	      /* x > y, x -= ulp */
		if(lx==0) {
		    if (hx==0) esx -= 1;
		    hx -= 1;
		}
		lx -= 1;
	    } else {				/* x < y, x += ulp */
		lx += 1;
		if(lx==0) {
		    hx += 1;
		    if (hx==0)
			esx += 1;
		}
	    }
	} else {				/* x < 0 */
	    if(esy>=0||(ix>iy||((ix==iy)&&(hx>hy||((hx==hy)&&(lx>ly)))))){
	      /* x < y, x -= ulp */
		if(lx==0) {
		    if (hx==0) esx -= 1;
		    hx -= 1;
		}
		lx -= 1;
	    } else {				/* x > y, x += ulp */
		lx += 1;
		if(lx==0) {
		    hx += 1;
		    if (hx==0) esx += 1;
		}
	    }
	}
	esy = esx&0x7fff;
	if(esy==0x7fff) return x+x;	/* overflow  */
	if(esy==0) {			/* underflow */
	    y = x*x;
	    if(y!=x) {		/* raise underflow flag */
	        SET_LDOUBLE_WORDS(y,esx,hx,lx);
		return y;
	    }
	}
	SET_LDOUBLE_WORDS(x,esx,hx,lx);
	return x;
}
weak_alias (__nextafterl, nextafterl)