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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2017-12-03 21:12:34 +0100
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2017-12-03 21:12:34 +0100
commitedce88cfef2f2a62647c2ab9536ca29694fab292 (patch)
tree5cfc13c44a91bb8b983ee137de38e136289db81e /libm/x86_64/fesetenv.c
parentc69db851309995c525b3993a10dc13dabdeb7b33 (diff)
x86_64: add fenv support from glibc
Diffstat (limited to 'libm/x86_64/fesetenv.c')
-rw-r--r--libm/x86_64/fesetenv.c112
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)