rockbox/firmware/asm/corelock.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 by Daniel Ankers
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "corelock.h"
/* Core locks using Peterson's mutual exclusion algorithm. */
#ifdef CPU_ARM
#include "arm/corelock.c"
#else
void corelock_lock(struct corelock *cl)
{
const unsigned int core = CURRENT_CORE;
const unsigned int othercore = 1 - core;
cl->myl[core] = core;
cl->turn = othercore;
for (;;)
{
if (cl->myl[othercore] == 0 || cl->turn == core)
break;
}
}
int corelock_try_lock(struct corelock *cl)
{
const unsigned int core = CURRENT_CORE;
const unsigned int othercore = 1 - core;
cl->myl[core] = core;
cl->turn = othercore;
if (cl->myl[othercore] == 0 || cl->turn == core)
{
return 1;
}
cl->myl[core] = 0;
return 0;
}
void corelock_unlock(struct corelock *cl)
{
cl->myl[CURRENT_CORE] = 0;
}
#endif