1/* s_nexttowardf.c -- float version of s_nextafter.c.
2 * Special i387 version.
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 */
5
6/*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
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
13 * is preserved.
14 * ====================================================
15 */
16
17#if defined(LIBM_SCCS) && !defined(lint)
18static char rcsid[] = "$NetBSD: $";
19#endif
20
21#include <errno.h>
22#include <math.h>
23#include <math-barriers.h>
24#include <math_private.h>
25#include <float.h>
26
27float __nexttowardf(float x, long double y)
28{
29 int32_t hx,ix,iy;
30 uint32_t hy,ly,esy;
31
32 GET_FLOAT_WORD(hx,x);
33 GET_LDOUBLE_WORDS(esy,hy,ly,y);
34 ix = hx&0x7fffffff; /* |x| */
35 iy = esy&0x7fff; /* |y| */
36
37 /* Intel's extended format has the normally implicit 1 explicit
38 present. Sigh! */
39 if((ix>0x7f800000) || /* x is nan */
40 (iy>=0x7fff&&(((hy&0x7fffffff)|ly)!=0))) /* y is nan */
41 return x+y;
42 if((long double) x==y) return y; /* x=y, return y */
43 if(ix==0) { /* x == 0 */
44 float u;
45 SET_FLOAT_WORD(x,((esy&0x8000)<<16)|1);/* return +-minsub*/
46 u = math_opt_barrier (x);
47 u = u * u;
48 math_force_eval (u); /* raise underflow flag */
49 return x;
50 }
51 if(hx>=0) { /* x > 0 */
52 if(x > y) { /* x -= ulp */
53 hx -= 1;
54 } else { /* x < y, x += ulp */
55 hx += 1;
56 }
57 } else { /* x < 0 */
58 if(x < y) { /* x -= ulp */
59 hx -= 1;
60 } else { /* x > y, x += ulp */
61 hx += 1;
62 }
63 }
64 hy = hx&0x7f800000;
65 if(hy>=0x7f800000) {
66 float u = x+x; /* overflow */
67 math_force_eval (u);
68 __set_errno (ERANGE);
69 }
70 if(hy<0x00800000) {
71 float u = x*x; /* underflow */
72 math_force_eval (u); /* raise underflow flag */
73 __set_errno (ERANGE);
74 }
75 SET_FLOAT_WORD(x,hx);
76 return x;
77}
78weak_alias (__nexttowardf, nexttowardf)
79