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18f2945ae9
This patch optimizes the FPSCR update on exception and rounding change functions by just updating its value if new value if different from current one. It also optimizes fedisableexcept and feenableexcept by removing an unecessary FPSCR read.
50 lines
1.7 KiB
C
50 lines
1.7 KiB
C
/* Store current floating-point environment and clear exceptions.
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Copyright (C) 1997-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <fenv_libc.h>
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#include <fpu_control.h>
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#define _FPU_MASK_ALL (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM | _FPU_MASK_XM | _FPU_MASK_IM)
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int
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feholdexcept (fenv_t *envp)
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{
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fenv_union_t old, new;
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/* Save the currently set exceptions. */
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old.fenv = *envp = fegetenv_register ();
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/* Clear everything except for the rounding modes and non-IEEE arithmetic
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flag. */
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new.l = old.l & 0xffffffff00000007LL;
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if (new.l == old.l)
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return 0;
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/* If the old env had any enabled exceptions, then mask SIGFPE in the
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MSR FE0/FE1 bits. This may allow the FPU to run faster because it
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always takes the default action and can not generate SIGFPE. */
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if ((old.l & _FPU_MASK_ALL) != 0)
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(void)__fe_mask_env ();
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/* Put the new state in effect. */
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fesetenv_register (new.fenv);
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return 0;
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}
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libm_hidden_def (feholdexcept)
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