1/* s_nexttowardf.c -- float version of s_nextafter.c.
2 * Special i387 version.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
16#if defined(LIBM_SCCS) && !defined(lint)
17static char rcsid[] = "$NetBSD: $";
18#endif
19
20#include <errno.h>
21#include <math.h>
22#include <math-barriers.h>
23#include <math_private.h>
24#include <float.h>
25
26float __nexttowardf(float x, long double y)
27{
28 int32_t hx,ix,iy;
29 uint32_t hy,ly,esy;
30
31 GET_FLOAT_WORD(hx,x);
32 GET_LDOUBLE_WORDS(esy,hy,ly,y);
33 ix = hx&0x7fffffff; /* |x| */
34 iy = esy&0x7fff; /* |y| */
35
36 /* Intel's extended format has the normally implicit 1 explicit
37 present. Sigh! */
38 if((ix>0x7f800000) || /* x is nan */
39 (iy>=0x7fff&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
40 return x+y;
41 if((long double) x==y) return y; /* x=y, return y */
42 if(ix==0) { /* x == 0 */
43 float u;
44 SET_FLOAT_WORD(x,((esy&0x8000)<<16)|1);/* return +-minsub*/
45 u = math_opt_barrier (x);
46 u = u * u;
47 math_force_eval (u); /* raise underflow flag */
48 return x;
49 }
50 if(hx>=0) { /* x > 0 */
51 if(x > y) { /* x -= ulp */
52 hx -= 1;
53 } else { /* x < y, x += ulp */
54 hx += 1;
55 }
56 } else { /* x < 0 */
57 if(x < y) { /* x -= ulp */
58 hx -= 1;
59 } else { /* x > y, x += ulp */
60 hx += 1;
61 }
62 }
63 hy = hx&0x7f800000;
64 if(hy>=0x7f800000) {
65 float u = x+x; /* overflow */
66 math_force_eval (u);
67 __set_errno (ERANGE);
68 }
69 if(hy<0x00800000) {
70 float u = x*x; /* underflow */
71 math_force_eval (u); /* raise underflow flag */
72 __set_errno (ERANGE);
73 }
74 SET_FLOAT_WORD(x,hx);
75 return x;
76}
77weak_alias (__nexttowardf, nexttowardf)
78