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