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Diffstat (limited to 'engines/tinsel/sched.cpp')
-rw-r--r-- | engines/tinsel/sched.cpp | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/engines/tinsel/sched.cpp b/engines/tinsel/sched.cpp new file mode 100644 index 0000000000..72cfeaf6b0 --- /dev/null +++ b/engines/tinsel/sched.cpp @@ -0,0 +1,345 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * 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 program 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 General Public License for more details. + + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + * Process scheduler. + */ + +#include "tinsel/sched.h" + +#include "common/util.h" + +namespace Tinsel { + +Scheduler *g_scheduler = 0; + +/** process structure */ +struct PROCESS { + PROCESS *pNext; //!< pointer to next process in active or free list + + CoroContext state; //!< the state of the coroutine + CORO_ADDR coroAddr; //!< the entry point of the coroutine + + int sleepTime; //!< number of scheduler cycles to sleep + int pid; //!< process ID + char param[PARAM_SIZE]; //!< process specific info +}; + + +Scheduler::Scheduler() { + processList = 0; + pFreeProcesses = 0; + pCurrent = 0; + +#ifdef DEBUG + // diagnostic process counters + numProcs = 0; + maxProcs = 0; +#endif + + pRCfunction = 0; + + active = new PROCESS; + + g_scheduler = this; // FIXME HACK +} + +Scheduler::~Scheduler() { + free(processList); + processList = NULL; + + delete active; + active = 0; +} + +/** + * Kills all processes and places them on the free list. + */ +void Scheduler::reset() { + +#ifdef DEBUG + // clear number of process in use + numProcs = 0; +#endif + + if (processList == NULL) { + // first time - allocate memory for process list + processList = (PROCESS *)calloc(NUM_PROCESS, sizeof(PROCESS)); + + // make sure memory allocated + if (processList == NULL) { + error("Cannot allocate memory for process data"); + } + + // fill with garbage + memset(processList, 'S', NUM_PROCESS * sizeof(PROCESS)); + } + + // no active processes + pCurrent = active->pNext = NULL; + + // place first process on free list + pFreeProcesses = processList; + + // link all other processes after first + for (int i = 1; i < NUM_PROCESS; i++) { + processList[i - 1].pNext = processList + i; + } + + // null the last process + processList[NUM_PROCESS - 1].pNext = NULL; +} + + +#ifdef DEBUG +/** + * Shows the maximum number of process used at once. + */ +void Scheduler::printStats(void) { + printf("%i process of %i used.\n", maxProcs, NUM_PROCESS); +} +#endif + + +/** + * Give all active processes a chance to run + */ +void Scheduler::schedule(void) { + // start dispatching active process list + PROCESS *pPrevProc = active; + PROCESS *pProc = active->pNext; + while (pProc != NULL) { + if (--pProc->sleepTime <= 0) { + // process is ready for dispatch, activate it + pCurrent = pProc; + pProc->coroAddr(pProc->state, pProc->param); + pCurrent = NULL; + if (!pProc->state || pProc->state->_sleep <= 0) { + // Coroutine finished + killProcess(pProc); + pProc = pPrevProc; + } else { + pProc->sleepTime = pProc->state->_sleep; + } + } + pPrevProc = pProc; + pProc = pProc->pNext; + } +} + + +/** + * Creates a new process. + * + * @param pid process identifier + * @param CORO_ADDR coroutine start address + * @param pParam process specific info + * @param sizeParam size of process specific info + */ +PROCESS *Scheduler::createProcess(int pid, CORO_ADDR coroAddr, const void *pParam, int sizeParam) { + PROCESS *pProc; + + // get a free process + pProc = pFreeProcesses; + + // trap no free process + assert(pProc != NULL); // Out of processes + +#ifdef DEBUG + // one more process in use + if (++numProcs > maxProcs) + maxProcs = numProcs; +#endif + + // get link to next free process + pFreeProcesses = pProc->pNext; + + if (pCurrent != NULL) { + // place new process before the next active process + pProc->pNext = pCurrent->pNext; + + // make this new process the next active process + pCurrent->pNext = pProc; + } else { // no active processes, place process at head of list + pProc->pNext = active->pNext; + active->pNext = pProc; + } + + // set coroutine entry point + pProc->coroAddr = coroAddr; + + // clear coroutine state + pProc->state = 0; + + // wake process up as soon as possible + pProc->sleepTime = 1; + + // set new process id + pProc->pid = pid; + + // set new process specific info + if (sizeParam) { + assert(sizeParam > 0 && sizeParam <= PARAM_SIZE); + + // set new process specific info + memcpy(pProc->param, pParam, sizeParam); + } + + + // return created process + return pProc; +} + +/** + * Kills the specified process. + * + * @param pKillProc which process to kill + */ +void Scheduler::killProcess(PROCESS *pKillProc) { + PROCESS *pProc, *pPrev; // process list pointers + + // make sure a valid process pointer + assert(pKillProc >= processList && pKillProc <= processList + NUM_PROCESS - 1); + + // can not kill the current process using killProcess ! + assert(pCurrent != pKillProc); + +#ifdef DEBUG + // one less process in use + --numProcs; + assert(numProcs >= 0); +#endif + + // search the active list for the process + for (pProc = active->pNext, pPrev = active; pProc != NULL; pPrev = pProc, pProc = pProc->pNext) { + if (pProc == pKillProc) { + // found process in active list + + // Free process' resources + if (pRCfunction != NULL) + (pRCfunction)(pProc); + + delete pProc->state; + + // make prev point to next to unlink pProc + pPrev->pNext = pProc->pNext; + + // link first free process after pProc + pProc->pNext = pFreeProcesses; + + // make pProc the first free process + pFreeProcesses = pProc; + + return; + } + } + + // process not found in active list if we get to here + error("killProcess(): tried to kill a process not in the list of active processes"); +} + + + +/** + * Returns a pointer to the currently running process. + */ +PROCESS *Scheduler::getCurrentProcess(void) { + return pCurrent; +} + +/** + * Returns the process identifier of the specified process. + * + * @param pProc which process + */ +int Scheduler::getCurrentPID() const { + PROCESS *pProc = pCurrent; + + // make sure a valid process pointer + assert(pProc >= processList && pProc <= processList + NUM_PROCESS - 1); + + // return processes PID + return pProc->pid; +} + +/** + * Kills any process matching the specified PID. The current + * process cannot be killed. + * + * @param pidKill process identifier of process to kill + * @param pidMask mask to apply to process identifiers before comparison + * @return The number of processes killed is returned. + */ +int Scheduler::killMatchingProcess(int pidKill, int pidMask) { + int numKilled = 0; + PROCESS *pProc, *pPrev; // process list pointers + + for (pProc = active->pNext, pPrev = active; pProc != NULL; pPrev = pProc, pProc = pProc->pNext) { + if ((pProc->pid & pidMask) == pidKill) { + // found a matching process + + // dont kill the current process + if (pProc != pCurrent) { + // kill this process + numKilled++; + + // make prev point to next to unlink pProc + pPrev->pNext = pProc->pNext; + + // link first free process after pProc + pProc->pNext = pFreeProcesses; + + // make pProc the first free process + pFreeProcesses = pProc; + + // set to a process on the active list + pProc = pPrev; + } + } + } + +#ifdef DEBUG + // adjust process in use + numProcs -= numKilled; + assert(numProcs >= 0); +#endif + + // return number of processes killed + return numKilled; +} + + + +/** + * Set pointer to a function to be called by killProcess(). + * + * May be called by a resource allocator, the function supplied is + * called by killProcess() to allow the resource allocator to free + * resources allocated to the dying process. + * + * @param pFunc Function to be called by killProcess() + */ +void Scheduler::setResourceCallback(VFPTRPP pFunc) { + pRCfunction = pFunc; +} + +} // end of namespace Tinsel |