| 1 | /* Copyright (C) 2009-2022 Free Software Foundation, Inc. |
|---|---|
| 2 | |
| 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 License as |
| 7 | published by the Free Software Foundation; either version 2.1 of the |
| 8 | 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 | |
| 22 | int |
| 23 | __feupdateenv (const fenv_t *envp) |
| 24 | { |
| 25 | fpu_control_t fpcr; |
| 26 | fpu_control_t fpcr_new; |
| 27 | fpu_control_t updated_fpcr; |
| 28 | fpu_fpsr_t fpsr; |
| 29 | fpu_fpsr_t fpsr_new; |
| 30 | int excepts; |
| 31 | |
| 32 | _FPU_GETCW (fpcr); |
| 33 | _FPU_GETFPSR (fpsr); |
| 34 | excepts = fpsr & FE_ALL_EXCEPT; |
| 35 | |
| 36 | if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV)) |
| 37 | { |
| 38 | fpcr_new = envp->__fpcr; |
| 39 | fpsr_new = envp->__fpsr | excepts; |
| 40 | |
| 41 | if (fpcr != fpcr_new) |
| 42 | _FPU_SETCW (fpcr_new); |
| 43 | |
| 44 | if (fpsr != fpsr_new) |
| 45 | _FPU_SETFPSR (fpsr_new); |
| 46 | |
| 47 | if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT)) |
| 48 | return __feraiseexcept (excepts: excepts); |
| 49 | |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | fpcr_new = fpcr & _FPU_RESERVED; |
| 54 | fpsr_new = fpsr & (_FPU_FPSR_RESERVED | FE_ALL_EXCEPT); |
| 55 | |
| 56 | if (envp == FE_DFL_ENV) |
| 57 | { |
| 58 | fpcr_new |= _FPU_DEFAULT; |
| 59 | fpsr_new |= _FPU_FPSR_DEFAULT; |
| 60 | } |
| 61 | else |
| 62 | { |
| 63 | fpcr_new |= _FPU_FPCR_IEEE; |
| 64 | fpsr_new |= _FPU_FPSR_IEEE; |
| 65 | } |
| 66 | |
| 67 | _FPU_SETFPSR (fpsr_new); |
| 68 | |
| 69 | if (fpcr != fpcr_new) |
| 70 | { |
| 71 | _FPU_SETCW (fpcr_new); |
| 72 | |
| 73 | /* Trapping exceptions are optional in AArch64; the relevant enable |
| 74 | bits in FPCR are RES0 hence the absence of support can be detected |
| 75 | by reading back the FPCR and comparing with the required value. */ |
| 76 | _FPU_GETCW (updated_fpcr); |
| 77 | |
| 78 | if (fpcr_new & ~updated_fpcr) |
| 79 | return 1; |
| 80 | } |
| 81 | |
| 82 | if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT)) |
| 83 | return __feraiseexcept (excepts: excepts); |
| 84 | |
| 85 | return 0; |
| 86 | } |
| 87 | libm_hidden_def (__feupdateenv) |
| 88 | weak_alias (__feupdateenv, feupdateenv) |
| 89 | libm_hidden_weak (feupdateenv) |
| 90 |