1 | /* Install given floating-point environment. |
2 | Copyright (C) 1997-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library. If not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <fenv.h> |
20 | |
21 | int |
22 | __fesetenv (const fenv_t *envp) |
23 | { |
24 | union { unsigned long long buf[4]; fenv_t env; } temp; |
25 | unsigned long long *bufptr; |
26 | |
27 | /* Install the environment specified by ENVP. But there are a few |
28 | values which we do not want to come from the saved environment. |
29 | Therefore, we get the current environment and replace the values |
30 | we want to use from the environment specified by the parameter. */ |
31 | bufptr = temp.buf; |
32 | __asm__ ( |
33 | "fstd %%fr0,0(%1)\n" |
34 | : "=m" (temp) : "r" (bufptr) : "%r0" ); |
35 | |
36 | temp.env.__status_word &= ~(FE_ALL_EXCEPT |
37 | | (FE_ALL_EXCEPT << 27) |
38 | | FE_DOWNWARD); |
39 | if (envp == FE_DFL_ENV) |
40 | temp.env.__status_word = 0; |
41 | else if (envp == FE_NOMASK_ENV) |
42 | temp.env.__status_word |= FE_ALL_EXCEPT; |
43 | else |
44 | temp.env.__status_word |= (envp->__status_word |
45 | & (FE_ALL_EXCEPT |
46 | | FE_DOWNWARD |
47 | | (FE_ALL_EXCEPT << 27))); |
48 | |
49 | /* Load the new environment. We use bufptr again since the |
50 | initial asm has modified the value of the register and here |
51 | we take advantage of that to load in reverse order so fr0 |
52 | is loaded last and T-Bit is enabled. */ |
53 | __asm__ ( |
54 | "fldd 0(%1),%%fr0\n" |
55 | : : "m" (temp), "r" (bufptr) : "%r0" ); |
56 | |
57 | /* Success. */ |
58 | return 0; |
59 | } |
60 | libm_hidden_def (__fesetenv) |
61 | weak_alias (__fesetenv, fesetenv) |
62 | libm_hidden_weak (fesetenv) |
63 | |