| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame^] | 1 | /* Install given floating-point environment and raise exceptions. |
| 2 | Copyright (C) 1997-2016 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
| 5 | |
| 6 | The GNU C Library is free software; you can redistribute it and/or |
| 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. |
| 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 |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library. If not, see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include <fenv.h> |
| 21 | #include <fpu_control.h> |
| 22 | #include <arm-features.h> |
| 23 | |
| 24 | |
| 25 | int |
| 26 | __feupdateenv (const fenv_t *envp) |
| 27 | { |
| 28 | fpu_control_t fpscr, new_fpscr, updated_fpscr; |
| 29 | int excepts; |
| 30 | |
| 31 | /* Fail if a VFP unit isn't present. */ |
| 32 | if (!ARM_HAVE_VFP) |
| 33 | return 1; |
| 34 | |
| 35 | _FPU_GETCW (fpscr); |
| 36 | excepts = fpscr & FE_ALL_EXCEPT; |
| 37 | |
| 38 | if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV)) |
| 39 | { |
| 40 | /* Merge current exception flags with the saved fenv. */ |
| 41 | new_fpscr = envp->__cw | excepts; |
| 42 | |
| 43 | /* Write new FPSCR if different (ignoring NZCV flags). */ |
| 44 | if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0) |
| 45 | _FPU_SETCW (new_fpscr); |
| 46 | |
| 47 | /* Raise the exceptions if enabled in the new FP state. */ |
| 48 | if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT)) |
| 49 | return __feraiseexcept (excepts); |
| 50 | |
| 51 | return 0; |
| 52 | } |
| 53 | |
| 54 | /* Preserve the reserved FPSCR flags. */ |
| 55 | new_fpscr = fpscr & (_FPU_RESERVED | FE_ALL_EXCEPT); |
| 56 | new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE; |
| 57 | |
| 58 | if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0) |
| 59 | { |
| 60 | _FPU_SETCW (new_fpscr); |
| 61 | |
| 62 | /* Not all VFP architectures support trapping exceptions, so |
| 63 | test whether the relevant bits were set and fail if not. */ |
| 64 | _FPU_GETCW (updated_fpscr); |
| 65 | |
| 66 | if (new_fpscr & ~updated_fpscr) |
| 67 | return 1; |
| 68 | } |
| 69 | |
| 70 | /* Raise the exceptions if enabled in the new FP state. */ |
| 71 | if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT)) |
| 72 | return __feraiseexcept (excepts); |
| 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | libm_hidden_def (__feupdateenv) |
| 77 | weak_alias (__feupdateenv, feupdateenv) |
| 78 | libm_hidden_weak (feupdateenv) |