55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/* Set the FPU control word for x86.
|
|
Copyright (C) 2003-2015 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
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 <math.h>
|
|
#include <fpu_control.h>
|
|
#include <fenv.h>
|
|
#include <unistd.h>
|
|
#include <ldsodefs.h>
|
|
#include <dl-procinfo.h>
|
|
|
|
void
|
|
__setfpucw (fpu_control_t set)
|
|
{
|
|
fpu_control_t cw;
|
|
|
|
/* Fetch the current control word. */
|
|
__asm__ ("fnstcw %0" : "=m" (*&cw));
|
|
|
|
/* Preserve the reserved bits, and set the rest as the user
|
|
specified (or the default, if the user gave zero). */
|
|
cw &= _FPU_RESERVED;
|
|
cw |= set & ~_FPU_RESERVED;
|
|
|
|
__asm__ ("fldcw %0" : : "m" (*&cw));
|
|
|
|
/* If the CPU supports SSE, we set the MXCSR as well. */
|
|
if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
|
|
{
|
|
unsigned int xnew_exc;
|
|
|
|
/* Get the current MXCSR. */
|
|
__asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
|
|
|
|
xnew_exc &= ~((0xc00 << 3) | (FE_ALL_EXCEPT << 7));
|
|
xnew_exc |= ((set & 0xc00) << 3) | ((set & FE_ALL_EXCEPT) << 7);
|
|
|
|
__asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
|
|
}
|
|
}
|