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/* Machine-dependent pthreads configuration and inline functions.
ARM version.
Copyright (C) 1997, 1998, 2000, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Philip Blundell <philb@gnu.org>.
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; see the file COPYING.LIB. If
not, see <http://www.gnu.org/licenses/>. */
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H 1
#include <sys/syscall.h>
#include <unistd.h>
#ifndef PT_EI
# define PT_EI __extern_always_inline
#endif
#if defined(__thumb__)
#if defined(__USE_LDREXSTREX__)
PT_EI long int ldrex(int *spinlock)
{
long int ret;
__asm__ __volatile__(
"ldrex %0, [%1]\n"
: "=r"(ret)
: "r"(spinlock) : "memory");
return ret;
}
PT_EI long int strex(int val, int *spinlock)
{
long int ret;
__asm__ __volatile__(
"strex %0, %1, [%2]\n"
: "=r"(ret)
: "r" (val), "r"(spinlock) : "memory");
return ret;
}
/* Spinlock implementation; required. */
PT_EI long int
testandset (int *spinlock)
{
register unsigned int ret;
do {
ret = ldrex(spinlock);
} while (strex(1, spinlock));
return ret;
}
#else /* __USE_LDREXSTREX__ */
/* This will not work on ARM1 or ARM2 because SWP is lacking on those
machines. Unfortunately we have no way to detect this at compile
time; let's hope nobody tries to use one. */
/* Spinlock implementation; required. */
PT_EI long int testandset (int *spinlock);
PT_EI long int testandset (int *spinlock)
{
register unsigned int ret;
void *pc;
__asm__ __volatile__(
".align 0\n"
"\tbx pc\n"
"\tnop\n"
"\t.arm\n"
"\tswp %0, %2, [%3]\n"
"\torr %1, pc, #1\n"
"\tbx %1\n"
"\t.force_thumb"
: "=r"(ret), "=r"(pc)
: "0"(1), "r"(spinlock));
return ret;
}
#endif
#else /* __thumb__ */
PT_EI long int testandset (int *spinlock);
PT_EI long int testandset (int *spinlock)
{
register unsigned int ret;
__asm__ __volatile__("swp %0, %1, [%2]"
: "=r"(ret)
: "0"(1), "r"(spinlock));
return ret;
}
#endif
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#define CURRENT_STACK_FRAME stack_pointer
register char * stack_pointer __asm__ ("sp");
#endif /* pt-machine.h */
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