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/*
* Copyright (c) 2001 Matteo Frigo
* Copyright (c) 2001 Massachusetts Institute of Technology
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "bench.h"
int aligned_main(int argc, char *argv[])
{
#if defined(__GNUC__) && defined(__i386__)
/*
* horrible hack to align the stack to a 16-byte boundary.
*
* We assume a gcc version >= 2.95 so that
* -mpreferred-stack-boundary works. Otherwise, all bets are
* off. However, -mpreferred-stack-boundary does not create a
* stack alignment, but it only preserves it. Unfortunately,
* many versions of libc on linux call main() with the wrong
* initial stack alignment, with the result that the code is now
* pessimally aligned instead of having a 50% chance of being
* correct.
*/
{
/*
* Use alloca to allocate some memory on the stack.
* This alerts gcc that something funny is going
* on, so that it does not omit the frame pointer
* etc.
*/
(void)__builtin_alloca(16);
/*
* Now align the stack pointer
*/
__asm__ __volatile__ ("andl $-16, %esp");
# ifdef FFTW_DEBUG_ALIGNMENT
/* pessimally align the stack, in order to check whether the
stack re-alignment hacks in FFTW3 work */
__asm__ __volatile__ ("addl $-4, %esp");
# endif
}
#endif
#ifdef __ICC /* Intel's compiler for ia32 */
{
/*
* Simply calling alloca seems to do the right thing.
* The size of the allocated block seems to be irrelevant.
*/
_alloca(16);
}
#endif
return bench_main(argc, argv);
}
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