diff options
Diffstat (limited to 'libm/x86_64/fesetmode.c')
-rw-r--r-- | libm/x86_64/fesetmode.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/libm/x86_64/fesetmode.c b/libm/x86_64/fesetmode.c new file mode 100644 index 000000000..487be9747 --- /dev/null +++ b/libm/x86_64/fesetmode.c @@ -0,0 +1,49 @@ +/* Install given floating-point control modes. x86_64 version. + Copyright (C) 2016-2017 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <fenv.h> +#include <fpu_control.h> + +/* All exceptions, including the x86-specific "denormal operand" + exception. */ +#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM) + +int +fesetmode (const femode_t *modep) +{ + fpu_control_t cw; + unsigned int mxcsr; + __asm__ ("stmxcsr %0" : "=m" (mxcsr)); + /* Preserve SSE exception flags but restore other state in + MXCSR. */ + mxcsr &= FE_ALL_EXCEPT_X86; + if (modep == FE_DFL_MODE) + { + cw = _FPU_DEFAULT; + /* Default MXCSR state has all bits zero except for those + masking exceptions. */ + mxcsr |= FE_ALL_EXCEPT_X86 << 7; + } + else + { + cw = modep->__control_word; + mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86; + } + _FPU_SETCW (cw); + __asm__ ("ldmxcsr %0" : : "m" (mxcsr)); + return 0; +} |