* nscd/Makefile (nscd-cflags): Set back to -fpie.
[glibc.git] / math / s_nextafter.c
blobd2af52dda38d280d0bf7c617b5542278e1581fbe
1 /* @(#)s_nextafter.c 5.1 93/09/24 */
2 /*
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
9 * is preserved.
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 $";
15 #endif
17 /* IEEE functions
18 * nextafter(x,y)
19 * return the next machine floating-point number of x in the
20 * direction toward y.
21 * Special cases:
24 /* Ugly hack so that the aliasing works. */
25 #define __nexttoward __internal___nexttoward
26 #define nexttoward __internal_nexttoward
28 #include <math.h>
29 #include <math_private.h>
30 #include <float.h>
32 #ifdef __STDC__
33 double __nextafter(double x, double y)
34 #else
35 double __nextafter(x,y)
36 double x,y;
37 #endif
39 int32_t hx,hy,ix,iy;
40 u_int32_t lx,ly;
42 EXTRACT_WORDS(hx,lx,x);
43 EXTRACT_WORDS(hy,ly,y);
44 ix = hx&0x7fffffff; /* |x| */
45 iy = hy&0x7fffffff; /* |y| */
47 if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
48 ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */
49 return x+y;
50 if(x==y) return y; /* x=y, return y */
51 if((ix|lx)==0) { /* x == 0 */
52 double u;
53 INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */
54 u = math_opt_barrier (x);
55 u = u*u;
56 math_force_eval (u); /* raise underflow flag */
57 return x;
59 if(hx>=0) { /* x > 0 */
60 if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */
61 if(lx==0) hx -= 1;
62 lx -= 1;
63 } else { /* x < y, x += ulp */
64 lx += 1;
65 if(lx==0) hx += 1;
67 } else { /* x < 0 */
68 if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
69 if(lx==0) hx -= 1;
70 lx -= 1;
71 } else { /* x > y, x += ulp */
72 lx += 1;
73 if(lx==0) hx += 1;
76 hy = hx&0x7ff00000;
77 if(hy>=0x7ff00000) {
78 x = x+x; /* overflow */
79 if (FLT_EVAL_METHOD != 0 && FLT_EVAL_METHOD != 1)
80 asm ("" : "+m"(x));
81 return x; /* overflow */
83 if(hy<0x00100000) {
84 double u = x*x; /* underflow */
85 math_force_eval (u); /* raise underflow flag */
87 INSERT_WORDS(x,hx,lx);
88 return x;
90 weak_alias (__nextafter, nextafter)
91 #ifdef NO_LONG_DOUBLE
92 strong_alias (__nextafter, __nextafterl)
93 weak_alias (__nextafter, nextafterl)
94 strong_alias (__nextafter, __nexttowardl)
95 weak_alias (__nexttowardl, nexttowardl)
96 #undef __nexttoward
97 strong_alias (__nextafter, __nexttoward)
98 #undef nexttoward
99 weak_alias (__nextafter, nexttoward)
100 #endif