1 | /* s_rintf.c -- float version of s_rint.c. |
2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
3 | */ |
4 | /* Adapted for use as nearbyint by Ulrich Drepper <drepper@cygnus.com>. */ |
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 | |
18 | #include <fenv.h> |
19 | #include <math.h> |
20 | #include <math_private.h> |
21 | |
22 | static const float |
23 | TWO23[2]={ |
24 | 8.3886080000e+06, /* 0x4b000000 */ |
25 | -8.3886080000e+06, /* 0xcb000000 */ |
26 | }; |
27 | |
28 | float |
29 | __nearbyintf(float x) |
30 | { |
31 | fenv_t env; |
32 | int32_t i0,j0,sx; |
33 | float w,t; |
34 | GET_FLOAT_WORD(i0,x); |
35 | sx = (i0>>31)&1; |
36 | j0 = ((i0>>23)&0xff)-0x7f; |
37 | if(j0<23) { |
38 | if(j0<0) { |
39 | libc_feholdexceptf (&env); |
40 | w = TWO23[sx]+x; |
41 | t = w-TWO23[sx]; |
42 | math_force_eval (t); |
43 | libc_fesetenvf (&env); |
44 | GET_FLOAT_WORD(i0,t); |
45 | SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31)); |
46 | return t; |
47 | } |
48 | } else { |
49 | if(__builtin_expect(j0==0x80, 0)) return x+x; /* inf or NaN */ |
50 | else return x; /* x is integral */ |
51 | } |
52 | libc_feholdexceptf (&env); |
53 | w = TWO23[sx]+x; |
54 | t = w-TWO23[sx]; |
55 | math_force_eval (t); |
56 | libc_fesetenvf (&env); |
57 | return t; |
58 | } |
59 | weak_alias (__nearbyintf, nearbyintf) |
60 | |