3 * Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support,
8 * ====================================================
9 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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
15 * ====================================================
18 #if defined(LIBM_SCCS) && !defined(lint)
19 static char rcsid[] = "$NetBSD: $";
24 * return the next machine floating-point number of x in the
30 #include <math_private.h>
33 double __nexttoward(double x, long double y)
36 u_int32_t lx,hy,ly,esy;
38 EXTRACT_WORDS(hx,lx,x);
39 GET_LDOUBLE_WORDS(esy,hy,ly,y);
40 ix = hx&0x7fffffff; /* |x| */
41 iy = esy&0x7fff; /* |y| */
43 /* Intel's extended format has the normally implicit 1 explicit
45 if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
46 ((iy>=0x7fff)&&((hy&0x7fffffff)|ly)!=0)) /* y is nan */
48 if((long double) x==y) return y; /* x=y, return y */
49 if((ix|lx)==0) { /* x == 0 */
51 INSERT_WORDS(x,(esy&0x8000)<<16,1); /* return +-minsub */
52 u = math_opt_barrier (x);
54 math_force_eval (u); /* raise underflow flag */
57 if(hx>=0) { /* x > 0 */
58 if (esy>=0x8000||((ix>>20)&0x7ff)>iy-0x3c00
59 || (((ix>>20)&0x7ff)==iy-0x3c00
60 && (((hx<<11)|(lx>>21))>(hy&0x7fffffff)
61 || (((hx<<11)|(lx>>21))==(hy&0x7fffffff)
62 && (lx<<11)>ly)))) { /* x > y, x -= ulp */
65 } else { /* x < y, x += ulp */
70 if (esy<0x8000||((ix>>20)&0x7ff)>iy-0x3c00
71 || (((ix>>20)&0x7ff)==iy-0x3c00
72 && (((hx<<11)|(lx>>21))>(hy&0x7fffffff)
73 || (((hx<<11)|(lx>>21))==(hy&0x7fffffff)
74 && (lx<<11)>ly)))) {/* x < y, x -= ulp */
77 } else { /* x > y, x += ulp */
84 x = x+x; /* overflow */
85 if (FLT_EVAL_METHOD != 0 && FLT_EVAL_METHOD != 1)
86 /* Force conversion to double. */
91 double u = x*x; /* underflow */
92 math_force_eval (u); /* raise underflow flag */
94 INSERT_WORDS(x,hx,lx);
97 weak_alias (__nexttoward, nexttoward)
99 strong_alias (__nexttoward, __nexttowardl)
100 weak_alias (__nexttoward, nexttowardl)