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-barriers.h> |
21 | #include <math_private.h> |
22 | #include <fenv_private.h> |
23 | #include <libm-alias-float.h> |
24 | #include <math-use-builtins.h> |
25 | |
26 | float |
27 | __nearbyintf (float x) |
28 | { |
29 | #if USE_NEARBYINTF_BUILTIN |
30 | return __builtin_nearbyintf (x); |
31 | #else |
32 | /* Use generic implementation. */ |
33 | static const float |
34 | TWO23[2] = { |
35 | 8.3886080000e+06, /* 0x4b000000 */ |
36 | -8.3886080000e+06, /* 0xcb000000 */ |
37 | }; |
38 | fenv_t env; |
39 | int32_t i0, j0, sx; |
40 | float w, t; |
41 | GET_FLOAT_WORD (i0, x); |
42 | sx = (i0 >> 31) & 1; |
43 | j0 = ((i0 >> 23) & 0xff) - 0x7f; |
44 | if (j0 < 23) |
45 | { |
46 | if (j0 < 0) |
47 | { |
48 | libc_feholdexceptf (&env); |
49 | w = TWO23[sx] + math_opt_barrier (x); |
50 | t = w - TWO23[sx]; |
51 | math_force_eval (t); |
52 | libc_fesetenvf (&env); |
53 | GET_FLOAT_WORD (i0, t); |
54 | SET_FLOAT_WORD (t, (i0 & 0x7fffffff) | (sx << 31)); |
55 | return t; |
56 | } |
57 | } |
58 | else |
59 | { |
60 | if (__glibc_unlikely (j0 == 0x80)) |
61 | return x + x; /* inf or NaN */ |
62 | else |
63 | return x; /* x is integral */ |
64 | } |
65 | libc_feholdexceptf (&env); |
66 | w = TWO23[sx] + math_opt_barrier (x); |
67 | t = w - TWO23[sx]; |
68 | math_force_eval (t); |
69 | libc_fesetenvf (&env); |
70 | return t; |
71 | #endif /* ! USE_NEARBYINT_BUILTIN */ |
72 | } |
73 | libm_alias_float (__nearbyint, nearbyint) |
74 | |