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-barriers.h>
32#include <math_private.h>
33#include <libm-alias-ldouble.h>
34
35long double __nextafterl(long double x, long double y)
36{
37 uint32_t hx,hy,ix,iy;
38 uint32_t lx,ly;
39 int32_t esx,esy;
40
41 GET_LDOUBLE_WORDS(esx,hx,lx,x);
42 GET_LDOUBLE_WORDS(esy,hy,ly,y);
43 ix = esx&0x7fff; /* |x| */
44 iy = esy&0x7fff; /* |y| */
45
46 /* Intel's extended format has the normally implicit 1 explicit
47 present. Sigh! */
48 if(((ix==0x7fff)&&(((hx&0x7fffffff)|lx)!=0)) || /* x is nan */
49 ((iy==0x7fff)&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
50 return x+y;
51 if(x==y) return y; /* x=y, return y */
52 if((ix|hx|lx)==0) { /* x == 0 */
53 long double u;
54 SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */
55 u = math_opt_barrier (x);
56 u = u * u;
57 math_force_eval (u); /* raise underflow flag */
58 return x;
59 }
60 if(esx>=0) { /* x > 0 */
61 if(esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
62 /* x > y, x -= ulp */
63 if(lx==0) {
64 if (hx <= 0x80000000) {
65 if (esx == 0) {
66 --hx;
67 } else {
68 esx -= 1;
69 hx = hx - 1;
70 if (esx > 0)
71 hx |= 0x80000000;
72 }
73 } else
74 hx -= 1;
75 }
76 lx -= 1;
77 } else { /* x < y, x += ulp */
78 lx += 1;
79 if(lx==0) {
80 hx += 1;
81 if (hx==0 || (esx == 0 && hx == 0x80000000)) {
82 esx += 1;
83 hx |= 0x80000000;
84 }
85 }
86 }
87 } else { /* x < 0 */
88 if(esy>=0||(esx>esy||((esx==esy)&&(hx>hy||((hx==hy)&&(lx>ly)))))){
89 /* x < y, x -= ulp */
90 if(lx==0) {
91 if (hx <= 0x80000000 && esx != 0xffff8000) {
92 esx -= 1;
93 hx = hx - 1;
94 if ((esx&0x7fff) > 0)
95 hx |= 0x80000000;
96 } else
97 hx -= 1;
98 }
99 lx -= 1;
100 } else { /* x > y, x += ulp */
101 lx += 1;
102 if(lx==0) {
103 hx += 1;
104 if (hx==0 || (esx == 0xffff8000 && hx == 0x80000000)) {
105 esx += 1;
106 hx |= 0x80000000;
107 }
108 }
109 }
110 }
111 esy = esx&0x7fff;
112 if(esy==0x7fff) {
113 long double u = x + x; /* overflow */
114 math_force_eval (u);
115 __set_errno (ERANGE);
116 }
117 if(esy==0) {
118 long double u = x*x; /* underflow */
119 math_force_eval (u); /* raise underflow flag */
120 __set_errno (ERANGE);
121 }
122 SET_LDOUBLE_WORDS(x,esx,hx,lx);
123 return x;
124}
125libm_alias_ldouble (__nextafter, nextafter)
126strong_alias (__nextafterl, __nexttowardl)
127weak_alias (__nextafterl, nexttowardl)
128