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/* Copyright (C) 2010 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* helpers for module initialization/shutdown.
*/
#include "precompiled.h"
#include "lib/module_init.h"
#include "lib/sysdep/cpu.h" // cpu_CAS
// not yet initialized, or already shutdown
static const ModuleInitState UNINITIALIZED = 0; // value documented in header
// running user callback - concurrent ModuleInit callers must spin
static const ModuleInitState BUSY = ERR::AGAIN; // never returned
// init succeeded; allow shutdown
static const ModuleInitState INITIALIZED = INFO::SKIPPED;
Status ModuleInit(volatile ModuleInitState* initState, Status (*init)())
{
for(;;)
{
if(cpu_CAS(initState, UNINITIALIZED, BUSY))
{
Status ret = init();
*initState = (ret == INFO::OK)? INITIALIZED : ret;
COMPILER_FENCE;
return ret;
}
const ModuleInitState latchedInitState = *initState;
if(latchedInitState == UNINITIALIZED || latchedInitState == BUSY)
{
cpu_Pause();
continue;
}
ENSURE(latchedInitState == INITIALIZED || latchedInitState < 0);
return (Status)latchedInitState;
}
}
Status ModuleShutdown(volatile ModuleInitState* initState, void (*shutdown)())
{
for(;;)
{
if(cpu_CAS(initState, INITIALIZED, BUSY))
{
shutdown();
*initState = UNINITIALIZED;
COMPILER_FENCE;
return INFO::OK;
}
const ModuleInitState latchedInitState = *initState;
if(latchedInitState == INITIALIZED || latchedInitState == BUSY)
{
cpu_Pause();
continue;
}
if(latchedInitState == UNINITIALIZED)
return INFO::SKIPPED;
ENSURE(latchedInitState < 0);
return (Status)latchedInitState;
}
}
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