diff options
Diffstat (limited to 'libm/x86_64/fesetenv.c')
| -rw-r--r-- | libm/x86_64/fesetenv.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/libm/x86_64/fesetenv.c b/libm/x86_64/fesetenv.c new file mode 100644 index 000000000..d194ee856 --- /dev/null +++ b/libm/x86_64/fesetenv.c @@ -0,0 +1,112 @@ +/* Install given floating-point environment. + Copyright (C) 2001-2017 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> +#include <assert.h> + +libm_hidden_proto(fesetenv) + +/* All exceptions, including the x86-specific "denormal operand" + exception. */ +#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM) + + +int +fesetenv (const fenv_t *envp) +{ + fenv_t temp; + + /* Install the environment specified by ENVP. But there are a few + values which we do not want to come from the saved environment. + Therefore, we get the current environment and replace the values + we want to use from the environment specified by the parameter. */ + __asm__ ("fnstenv %0\n" + "stmxcsr %1" : "=m" (*&temp), "=m" (*&temp.__mxcsr)); + + if (envp == FE_DFL_ENV) + { + temp.__control_word |= FE_ALL_EXCEPT_X86; + temp.__control_word &= ~FE_TOWARDZERO; + temp.__control_word |= _FPU_EXTENDED; + temp.__status_word &= ~FE_ALL_EXCEPT_X86; + temp.__eip = 0; + temp.__cs_selector = 0; + temp.__opcode = 0; + temp.__data_offset = 0; + temp.__data_selector = 0; + /* Clear SSE exceptions. */ + temp.__mxcsr &= ~FE_ALL_EXCEPT_X86; + /* Set mask for SSE MXCSR. */ + temp.__mxcsr |= (FE_ALL_EXCEPT_X86 << 7); + /* Set rounding to FE_TONEAREST. */ + temp.__mxcsr &= ~ 0x6000; + temp.__mxcsr |= (FE_TONEAREST << 3); + /* Clear the FZ and DAZ bits. */ + temp.__mxcsr &= ~0x8040; + } + else if (envp == FE_NOMASK_ENV) + { + temp.__control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDZERO); + /* Keep the "denormal operand" exception masked. */ + temp.__control_word |= __FE_DENORM; + temp.__control_word |= _FPU_EXTENDED; + temp.__status_word &= ~FE_ALL_EXCEPT_X86; + temp.__eip = 0; + temp.__cs_selector = 0; + temp.__opcode = 0; + temp.__data_offset = 0; + temp.__data_selector = 0; + /* Clear SSE exceptions. */ + temp.__mxcsr &= ~FE_ALL_EXCEPT_X86; + /* Set mask for SSE MXCSR. */ + /* Set rounding to FE_TONEAREST. */ + temp.__mxcsr &= ~ 0x6000; + temp.__mxcsr |= (FE_TONEAREST << 3); + /* Do not mask exceptions. */ + temp.__mxcsr &= ~(FE_ALL_EXCEPT << 7); + /* Keep the "denormal operand" exception masked. */ + temp.__mxcsr |= (__FE_DENORM << 7); + /* Clear the FZ and DAZ bits. */ + temp.__mxcsr &= ~0x8040; + } + else + { + temp.__control_word &= ~(FE_ALL_EXCEPT_X86 + | FE_TOWARDZERO + | _FPU_EXTENDED); + temp.__control_word |= (envp->__control_word + & (FE_ALL_EXCEPT_X86 + | FE_TOWARDZERO + | _FPU_EXTENDED)); + temp.__status_word &= ~FE_ALL_EXCEPT_X86; + temp.__status_word |= envp->__status_word & FE_ALL_EXCEPT_X86; + temp.__eip = envp->__eip; + temp.__cs_selector = envp->__cs_selector; + temp.__opcode = envp->__opcode; + temp.__data_offset = envp->__data_offset; + temp.__data_selector = envp->__data_selector; + temp.__mxcsr = envp->__mxcsr; + } + + __asm__ ("fldenv %0\n" + "ldmxcsr %1" : : "m" (temp), "m" (temp.__mxcsr)); + + /* Success. */ + return 0; +} +libm_hidden_def(fesetenv) |