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/*
* sysdeps/microblaze/pt-machine.h -- microblaze-specific pthread definitions
*
* Copyright (C) 2003 John Williams <jwilliams@itee.uq.edu.au>
* Copyright (C) 2002 NEC Electronics Corporation
* Copyright (C) 2002 Miles Bader <miles@gnu.org>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License. See the file COPYING.LIB in the main
* directory of this archive for more details.
*
* Written by Miles Bader <miles@gnu.org>
*/
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H 1
#include <features.h>
#ifndef PT_EI
# define PT_EI extern inline
#endif
extern long int testandset (int *spinlock);
extern int __compare_and_swap (long *ptr, long old, long new);
/* 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__ ("r1");
#define HAS_COMPARE_AND_SWAP
#define HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS
#define IMPLEMENT_TAS_WITH_CAS
/* Atomically: If *PTR == OLD, set *PTR to NEW and return true,
otherwise do nothing and return false. */
PT_EI int __compare_and_swap (long *ptr, long old, long new)
{
unsigned long psw;
/* disable interrupts */
/* This is ugly ugly ugly! */
__asm__ __volatile__ ("mfs %0, rmsr;"
"andi r3, %0, ~2;"
"mts rmsr, r3;"
: "=&r" (psw)
:
: "r3");
if (likely (*ptr == old))
{
*ptr = new;
__asm__ __volatile__ ("mts rmsr, %0;" :: "r" (psw)); /* re-enable */
return 1;
}
else
{
__asm__ __volatile__ ("mts rmsr, %0;" :: "r" (psw)); /* re-enable */
return 0;
}
}
/* like above's __compare_and_swap() but it first syncs the memory
(This is also the difference between both functions in e.g.
../powerpc/pt-machine.h)
Doing this additional sync fixes a hang of __pthread_alt_unlock()
(Falk Brettschneider <fbrettschneider@baumeroptronic.de>) */
PT_EI int
__compare_and_swap_with_release_semantics (long *p,
long oldval, long newval)
{
__asm__ __volatile__ ("" : : : "memory"); /*MEMORY_BARRIER ();*/
return __compare_and_swap (p, oldval, newval);
}
#ifndef IMPLEMENT_TAS_WITH_CAS
/* Spinlock implementation; required. */
PT_EI long int testandset (int *spinlock)
{
unsigned psw;
/* disable interrupts */
__asm__ __volatile__ ("mfs %0, rmsr;"
"andi r3, %0, ~2;"
"mts rmsr, r3;"
: "=&r" (psw)
:
: "r3");
if (*spinlock)
{
/* Enable ints */
__asm__ __volatile__ ("mts rmsr, %0;" :: "r" (psw));
return 1;
} else {
*spinlock=1;
/* Enable ints */
__asm__ __volatile__ ("mts rmsr, %0;" :: "r" (psw));
return 0;
}
}
#endif
#endif /* pt-machine.h */
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