1 | /* Install given floating-point environment and raise exceptions. |
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 | #include <fpu_control.h> |
21 | #include <arm-features.h> |
22 | |
23 | |
24 | int |
25 | __feupdateenv (const fenv_t *envp) |
26 | { |
27 | fpu_control_t fpscr, new_fpscr, updated_fpscr; |
28 | int excepts; |
29 | |
30 | /* Fail if a VFP unit isn't present. */ |
31 | if (!ARM_HAVE_VFP) |
32 | return 1; |
33 | |
34 | _FPU_GETCW (fpscr); |
35 | excepts = fpscr & FE_ALL_EXCEPT; |
36 | |
37 | if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV)) |
38 | { |
39 | /* Merge current exception flags with the saved fenv. */ |
40 | new_fpscr = envp->__cw | excepts; |
41 | |
42 | /* Write new FPSCR if different (ignoring NZCV flags). */ |
43 | if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0) |
44 | _FPU_SETCW (new_fpscr); |
45 | |
46 | /* Raise the exceptions if enabled in the new FP state. */ |
47 | if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT)) |
48 | return __feraiseexcept (excepts: excepts); |
49 | |
50 | return 0; |
51 | } |
52 | |
53 | /* Preserve the reserved FPSCR flags. */ |
54 | new_fpscr = fpscr & (_FPU_RESERVED | FE_ALL_EXCEPT); |
55 | new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE; |
56 | |
57 | if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0) |
58 | { |
59 | _FPU_SETCW (new_fpscr); |
60 | |
61 | /* Not all VFP architectures support trapping exceptions, so |
62 | test whether the relevant bits were set and fail if not. */ |
63 | _FPU_GETCW (updated_fpscr); |
64 | |
65 | if (new_fpscr & ~updated_fpscr) |
66 | return 1; |
67 | } |
68 | |
69 | /* Raise the exceptions if enabled in the new FP state. */ |
70 | if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT)) |
71 | return __feraiseexcept (excepts: excepts); |
72 | |
73 | return 0; |
74 | } |
75 | libm_hidden_def (__feupdateenv) |
76 | weak_alias (__feupdateenv, feupdateenv) |
77 | libm_hidden_weak (feupdateenv) |
78 | |