2 * Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support,
3 * drepper@cygnus.com and Jakub Jelinek, jj@ultra.linux.cz.
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
14 * ====================================================
17 #if defined(LIBM_SCCS) && !defined(lint)
18 static char rcsid[] = "$NetBSD: $";
23 * return the next machine floating-point number of x in the
29 #include <math_private.h>
30 #include <math_ldbl_opt.h>
34 double __nexttoward(double x, long double y)
36 double __nexttoward(x,y)
46 EXTRACT_WORDS(hx,lx,x);
47 GET_LDOUBLE_WORDS64(hy,ly,y);
48 ix = hx&0x7fffffff; /* |x| */
49 iy = hy&0x7fffffffffffffffLL; /* |y| */
50 uly = ly&0x7fffffffffffffffLL; /* |y| */
52 if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
53 ((iy>=0x7ff0000000000000LL)&&((iy-0x7ff0000000000000LL)|uly)!=0))
56 if((long double) x==y) return y; /* x=y, return y */
57 if((ix|lx)==0) { /* x == 0 */
59 INSERT_WORDS(x,(u_int32_t)((hy>>32)&0x80000000),1);/* return +-minsub */
60 u = math_opt_barrier (x);
62 math_force_eval (u); /* raise underflow flag */
65 if(hx>=0) { /* x > 0 */
66 if (hy<0||(ix>>20)>(iy>>52)
67 || ((ix>>20)==(iy>>52)
68 && (((((int64_t)hx)<<32)|(lx))>(hy&0x000fffffffffffffLL)
69 || (((((int64_t)hx)<<32)|(lx))==(hy&0x000fffffffffffffLL)
70 )))) { /* x > y, x -= ulp */
73 } else { /* x < y, x += ulp */
78 if (hy>=0||(ix>>20)>(iy>>52)
79 || ((ix>>20)==(iy>>52)
80 && (((((int64_t)hx)<<32)|(lx))>(hy&0x000fffffffffffffLL)
81 || (((((int64_t)hx)<<32)|(lx))==(hy&0x000fffffffffffffLL)
82 )))) { /* x < y, x -= ulp */
85 } else { /* x > y, x += ulp */
92 x = x+x; /* overflow */
93 if (FLT_EVAL_METHOD != 0 && FLT_EVAL_METHOD != 1)
94 /* Force conversion to double. */
99 double u = x*x; /* underflow */
100 math_force_eval (u); /* raise underflow flag */
102 INSERT_WORDS(x,hx,lx);
105 long_double_symbol (libm, __nexttoward, nexttoward);