1 /* Install given floating-point control modes. x86_64 version. 2 Copyright (C) 2016-2017 Free Software Foundation, Inc. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <http://www.gnu.org/licenses/>. */ 17 18 #include <fenv.h> 19 #include <fpu_control.h> 20 21 /* All exceptions, including the x86-specific "denormal operand" 22 exception. */ 23 #define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM) 24 25 int fesetmode(const femode_t * modep)26fesetmode (const femode_t *modep) 27 { 28 fpu_control_t cw; 29 unsigned int mxcsr; 30 __asm__ ("stmxcsr %0" : "=m" (mxcsr)); 31 /* Preserve SSE exception flags but restore other state in 32 MXCSR. */ 33 mxcsr &= FE_ALL_EXCEPT_X86; 34 if (modep == FE_DFL_MODE) 35 { 36 cw = _FPU_DEFAULT; 37 /* Default MXCSR state has all bits zero except for those 38 masking exceptions. */ 39 mxcsr |= FE_ALL_EXCEPT_X86 << 7; 40 } 41 else 42 { 43 cw = modep->__control_word; 44 mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86; 45 } 46 _FPU_SETCW (cw); 47 __asm__ ("ldmxcsr %0" : : "m" (mxcsr)); 48 return 0; 49 } 50