1/* s_nextafterl.c -- long double version of s_nextafter.c.
2 * Special version for i387.
3 * Conversion to long double by Ulrich Drepper,
4 * Cygnus Support, drepper@cygnus.com.
5 */
6
7/*
8 * ====================================================
9 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 *
11 * Developed at SunPro, a Sun Microsystems, Inc. business.
12 * Permission to use, copy, modify, and distribute this
13 * software is freely granted, provided that this notice
14 * is preserved.
15 * ====================================================
16 */
17
18#if defined(LIBM_SCCS) && !defined(lint)
19static char rcsid[] = "$NetBSD: $";
20#endif
21
22/* IEEE functions
23 * nextafterl(x,y)
24 * return the next machine floating-point number of x in the
25 * direction toward y.
26 * Special cases:
27 */
28
29#include <errno.h>
30#include <math.h>
31#include <math_private.h>
32
33long double __nextafterl(long double x, long double y)
34{
35 u_int32_t hx,hy,ix,iy;
36 u_int32_t lx,ly;
37 int32_t esx,esy;
38
39 GET_LDOUBLE_WORDS(esx,hx,lx,x);
40 GET_LDOUBLE_WORDS(esy,hy,ly,y);
41 ix = esx&0x7fff; /* |x| */
42 iy = esy&0x7fff; /* |y| */
43
44 /* Intel's extended format has the normally implicit 1 explicit
45 present. Sigh! */
46 if(((ix==0x7fff)&&(((hx&0x7fffffff)|lx)!=0)) || /* x is nan */
47 ((iy==0x7fff)&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
48 return x+y;
49 if(x==y) return y; /* x=y, return y */
50 if((ix|hx|lx)==0) { /* x == 0 */
51 long double u;
52 SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */
53 u = math_opt_barrier (x);
54 u = u * u;
55 math_force_eval (u); /* raise underflow flag */
56 return x;
57 }
58 if(esx>=0) { /* x > 0 */
59 if(esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
60 /* x > y, x -= ulp */
61 if(lx==0) {
62 if (hx <= 0x80000000) {
63 if (esx == 0) {
64 --hx;
65 } else {
66 esx -= 1;
67 hx = hx - 1;
68 if (esx > 0)
69 hx |= 0x80000000;
70 }
71 } else
72 hx -= 1;
73 }
74 lx -= 1;
75 } else { /* x < y, x += ulp */
76 lx += 1;
77 if(lx==0) {
78 hx += 1;
79 if (hx==0 || (esx == 0 && hx == 0x80000000)) {
80 esx += 1;
81 hx |= 0x80000000;
82 }
83 }
84 }
85 } else { /* x < 0 */
86 if(esy>=0||(esx>esy||((esx==esy)&&(hx>hy||((hx==hy)&&(lx>ly)))))){
87 /* x < y, x -= ulp */
88 if(lx==0) {
89 if (hx <= 0x80000000 && esx != 0xffff8000) {
90 esx -= 1;
91 hx = hx - 1;
92 if ((esx&0x7fff) > 0)
93 hx |= 0x80000000;
94 } else
95 hx -= 1;
96 }
97 lx -= 1;
98 } else { /* x > y, x += ulp */
99 lx += 1;
100 if(lx==0) {
101 hx += 1;
102 if (hx==0 || (esx == 0xffff8000 && hx == 0x80000000)) {
103 esx += 1;
104 hx |= 0x80000000;
105 }
106 }
107 }
108 }
109 esy = esx&0x7fff;
110 if(esy==0x7fff) {
111 long double u = x + x; /* overflow */
112 math_force_eval (u);
113 __set_errno (ERANGE);
114 }
115 if(esy==0) {
116 long double u = x*x; /* underflow */
117 math_force_eval (u); /* raise underflow flag */
118 __set_errno (ERANGE);
119 }
120 SET_LDOUBLE_WORDS(x,esx,hx,lx);
121 return x;
122}
123weak_alias (__nextafterl, nextafterl)
124strong_alias (__nextafterl, __nexttowardl)
125weak_alias (__nextafterl, nexttowardl)
126