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6d4752d8 | 1 | /* Install given floating-point environment and raise exceptions. |
04277e02 | 2 | Copyright (C) 1997-2019 Free Software Foundation, Inc. |
6d4752d8 | 3 | This file is part of the GNU C Library. |
7210de33 | 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
6d4752d8 UD |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
6d4752d8 UD |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
6d4752d8 | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
6d4752d8 | 19 | |
7210de33 | 20 | #include <fenv_libc.h> |
edba7a54 | 21 | #include <fpu_control.h> |
6d4752d8 | 22 | |
edba7a54 UD |
23 | #define _FPU_MASK_ALL (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM | _FPU_MASK_XM | _FPU_MASK_IM) |
24 | ||
63ae7b63 UD |
25 | int |
26 | __feupdateenv (const fenv_t *envp) | |
6d4752d8 | 27 | { |
7210de33 | 28 | fenv_union_t old, new; |
6d4752d8 | 29 | |
7210de33 UD |
30 | /* Save the currently set exceptions. */ |
31 | new.fenv = *envp; | |
32 | old.fenv = fegetenv_register (); | |
6d4752d8 | 33 | |
4a59e9ad UD |
34 | /* Restore rounding mode and exception enable from *envp and merge |
35 | exceptions. Leave fraction rounded/inexact and FP result/CC bits | |
36 | unchanged. */ | |
4a28b3ca | 37 | new.l = (old.l & 0xffffffff1fffff00LL) | (new.l & 0x1ff80fff); |
9c84384c | 38 | |
2ccdea26 | 39 | /* If the old env has no enabled exceptions and the new env has any enabled |
4a59e9ad UD |
40 | exceptions, then unmask SIGFPE in the MSR FE0/FE1 bits. This will put |
41 | the hardware into "precise mode" and may cause the FPU to run slower on | |
42 | some hardware. */ | |
4a28b3ca | 43 | if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0) |
bd12ab55 | 44 | (void) __fe_nomask_env_priv (); |
9c84384c | 45 | |
2ccdea26 | 46 | /* If the old env had any enabled exceptions and the new env has no enabled |
4a59e9ad | 47 | exceptions, then mask SIGFPE in the MSR FE0/FE1 bits. This may allow the |
9c84384c | 48 | FPU to run faster because it always takes the default action and can not |
4a59e9ad | 49 | generate SIGFPE. */ |
4a28b3ca | 50 | if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0) |
4a59e9ad | 51 | (void)__fe_mask_env (); |
6d4752d8 | 52 | |
7210de33 UD |
53 | /* Atomically enable and raise (if appropriate) exceptions set in `new'. */ |
54 | fesetenv_register (new.fenv); | |
63ae7b63 UD |
55 | |
56 | /* Success. */ | |
57 | return 0; | |
6d4752d8 | 58 | } |
4eb8a862 RM |
59 | |
60 | #include <shlib-compat.h> | |
61 | #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2) | |
63ae7b63 | 62 | strong_alias (__feupdateenv, __old_feupdateenv) |
e97ed6dd | 63 | compat_symbol (libm, __old_feupdateenv, feupdateenv, GLIBC_2_1); |
4eb8a862 RM |
64 | #endif |
65 | ||
8116321f | 66 | libm_hidden_def (__feupdateenv) |
9ff8d36f | 67 | libm_hidden_ver (__feupdateenv, feupdateenv) |
e97ed6dd | 68 | versioned_symbol (libm, __feupdateenv, feupdateenv, GLIBC_2_2); |