1 | /* s_nexttowardf.c -- float version of s_nextafter.c. |
2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com |
3 | * and Jakub Jelinek, jj@ultra.linux.cz. |
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) |
18 | static 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 <math_ldbl_opt.h> |
26 | #include <float.h> |
27 | |
28 | float __nexttowardf(float x, long double y) |
29 | { |
30 | int32_t hx,ix; |
31 | int64_t hy,iy; |
32 | double yhi; |
33 | |
34 | GET_FLOAT_WORD(hx,x); |
35 | yhi = ldbl_high (y); |
36 | EXTRACT_WORDS64 (hy, yhi); |
37 | ix = hx&0x7fffffff; /* |x| */ |
38 | iy = hy&0x7fffffffffffffffLL; /* |y| */ |
39 | |
40 | if((ix>0x7f800000) || /* x is nan */ |
41 | (iy>0x7ff0000000000000LL)) |
42 | /* y is nan */ |
43 | return x+y; |
44 | if((long double) x==y) return y; /* x=y, return y */ |
45 | if(ix==0) { /* x == 0 */ |
46 | float u; |
47 | SET_FLOAT_WORD(x,(uint32_t)((hy>>32)&0x80000000)|1);/* return +-minsub*/ |
48 | u = math_opt_barrier (x); |
49 | u = u * u; |
50 | math_force_eval (u); /* raise underflow flag */ |
51 | return x; |
52 | } |
53 | if(hx>=0) { /* x > 0 */ |
54 | if(x > y) { /* x -= ulp */ |
55 | hx -= 1; |
56 | } else { /* x < y, x += ulp */ |
57 | hx += 1; |
58 | } |
59 | } else { /* x < 0 */ |
60 | if(x < y) { /* x -= ulp */ |
61 | hx -= 1; |
62 | } else { /* x > y, x += ulp */ |
63 | hx += 1; |
64 | } |
65 | } |
66 | hy = hx&0x7f800000; |
67 | if(hy>=0x7f800000) { |
68 | float u = x+x; /* overflow */ |
69 | math_force_eval (u); |
70 | __set_errno (ERANGE); |
71 | } |
72 | if(hy<0x00800000) { /* underflow */ |
73 | float u = x*x; |
74 | math_force_eval (u); /* raise underflow flag */ |
75 | __set_errno (ERANGE); |
76 | } |
77 | SET_FLOAT_WORD(x,hx); |
78 | return x; |
79 | } |
80 | long_double_symbol (libm, __nexttowardf, nexttowardf); |
81 | |