mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-01 17:30:07 +00:00
cd7ce12a02
The exceptions passed to fe{en,dis}ableexcept() are defined in the ABI
as a bitmask, a combination of FE_INVALID, FE_OVERFLOW, etc.
Within the functions, these bits must be translated to/from the corresponding
enable bits in the Floating Point Status Control Register (FPSCR).
This translation is currently done bit-by-bit. The compiler generates
a series of conditional bit operations. Nicely, the "FE" exception
bits are all a uniform offset from the FPSCR enable bits, so the bit-by-bit
operation can instead be performed by a shift with appropriate masking.
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* Enable floating-point exceptions.
|
|
Copyright (C) 2000-2019 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Geoffrey Keating <geoffk@geoffk.org>, 2000.
|
|
|
|
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_libc.h>
|
|
|
|
int
|
|
feenableexcept (int excepts)
|
|
{
|
|
fenv_union_t fe, curr;
|
|
int result, new;
|
|
|
|
/* Get current exception mask to return. */
|
|
fe.fenv = curr.fenv = fegetenv_register ();
|
|
result = fenv_reg_to_exceptions (fe.l);
|
|
|
|
if ((excepts & FE_ALL_INVALID) == FE_ALL_INVALID)
|
|
excepts = (excepts | FE_INVALID) & ~ FE_ALL_INVALID;
|
|
|
|
/* Sets the new exception mask. */
|
|
fe.l |= fenv_exceptions_to_reg (excepts);
|
|
|
|
if (fe.l != curr.l)
|
|
fesetenv_register (fe.fenv);
|
|
|
|
new = __fegetexcept ();
|
|
if (new != 0 && result == 0)
|
|
(void) __fe_nomask_env_priv ();
|
|
|
|
if ((new & excepts) != excepts)
|
|
result = -1;
|
|
|
|
return result;
|
|
}
|