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 __fesetenv(const fenv_t * envp)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