1 /* Install given floating-point control modes. i386 version. 2 Copyright (C) 2016-2022 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 <unistd.h> 22 #include <ldsodefs.h> 23 #include <dl-procinfo.h> 24 25 /* All exceptions, including the x86-specific "denormal operand" 26 exception. */ 27 #define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM) 28 29 int fesetmode(const femode_t * modep)30fesetmode (const femode_t *modep) 31 { 32 fpu_control_t cw; 33 if (modep == FE_DFL_MODE) 34 cw = _FPU_DEFAULT; 35 else 36 cw = modep->__control_word; 37 _FPU_SETCW (cw); 38 if (CPU_FEATURE_USABLE (SSE)) 39 { 40 unsigned int mxcsr; 41 __asm__ ("stmxcsr %0" : "=m" (mxcsr)); 42 /* Preserve SSE exception flags but restore other state in 43 MXCSR. */ 44 mxcsr &= FE_ALL_EXCEPT_X86; 45 if (modep == FE_DFL_MODE) 46 /* Default MXCSR state has all bits zero except for those 47 masking exceptions. */ 48 mxcsr |= FE_ALL_EXCEPT_X86 << 7; 49 else 50 mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86; 51 __asm__ ("ldmxcsr %0" : : "m" (mxcsr)); 52 } 53 return 0; 54 } 55