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https://opencores.org/ocsvn/eco32/eco32/trunk
Subversion Repositories eco32
[/] [eco32/] [trunk/] [sim/] [timer.c] - Rev 297
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/* * timer.c -- timer simulation */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <setjmp.h> #include "common.h" #include "console.h" #include "error.h" #include "except.h" #include "cpu.h" #include "timer.h" #define TIME_WRAP 1000000 /* avoid overflow of current time */ /* * data structure for simulation timer */ typedef struct timer { struct timer *next; int alarm; void (*callback)(int param); int param; } Timer; /* * data structure for timer/counter device */ typedef struct { Word ctrl; Word divisor; Word counter; int irq; } TimerCounter; static Bool debug = false; static Timer *activeTimers = NULL; static Timer *freeTimers = NULL; static int currentTime = 0; /* measured in clock cycles */ static TimerCounter timerCounters[NUMBER_TMRCNT]; Word timerRead(Word addr) { int dev, reg; Word data; if (debug) { cPrintf("\n**** TIMER READ from 0x%08X", addr); } dev = addr >> 12; if (dev >= NUMBER_TMRCNT) { /* illegal device */ throwException(EXC_BUS_TIMEOUT); } reg = addr & 0x0FFF; if (reg == TIMER_CTRL) { data = timerCounters[dev].ctrl; } else if (reg == TIMER_DIVISOR) { data = timerCounters[dev].divisor; } else if (reg == TIMER_COUNTER) { data = timerCounters[dev].counter; } else { /* illegal register */ throwException(EXC_BUS_TIMEOUT); } if (debug) { cPrintf(", data = 0x%08X ****\n", data); } return data; } void timerWrite(Word addr, Word data) { int dev, reg; if (debug) { cPrintf("\n**** TIMER WRITE to 0x%08X, data = 0x%08X ****\n", addr, data); } dev = addr >> 12; if (dev >= NUMBER_TMRCNT) { /* illegal device */ throwException(EXC_BUS_TIMEOUT); } reg = addr & 0x0FFF; if (reg == TIMER_CTRL) { if (data & TIMER_IEN) { timerCounters[dev].ctrl |= TIMER_IEN; } else { timerCounters[dev].ctrl &= ~TIMER_IEN; } if (data & TIMER_EXP) { timerCounters[dev].ctrl |= TIMER_EXP; } else { timerCounters[dev].ctrl &= ~TIMER_EXP; } if ((timerCounters[dev].ctrl & TIMER_IEN) != 0 && (timerCounters[dev].ctrl & TIMER_EXP) != 0) { /* raise timer interrupt */ cpuSetInterrupt(timerCounters[dev].irq); } else { /* lower timer interrupt */ cpuResetInterrupt(timerCounters[dev].irq); } } else if (reg == TIMER_DIVISOR) { timerCounters[dev].divisor = data; timerCounters[dev].counter = data; } else { /* illegal register */ throwException(EXC_BUS_TIMEOUT); } } void timerTick(void) { Timer *timer; void (*callback)(int param); int param; int i; /* increment current time */ currentTime += CC_PER_INSTR; /* avoid overflow */ if (currentTime >= TIME_WRAP) { currentTime -= TIME_WRAP; timer = activeTimers; while (timer != NULL) { timer->alarm -= TIME_WRAP; timer = timer->next; } } /* check whether any simulation timer expired */ while (activeTimers != NULL && currentTime >= activeTimers->alarm) { timer = activeTimers; activeTimers = timer->next; callback = timer->callback; param = timer->param; timer->next = freeTimers; freeTimers = timer; (*callback)(param); } /* decrement counters and check if an interrupt must be raised */ for (i = 0; i < NUMBER_TMRCNT; i++) { if (timerCounters[i].counter <= CC_PER_INSTR) { timerCounters[i].counter += timerCounters[i].divisor - CC_PER_INSTR; timerCounters[i].ctrl |= TIMER_EXP; if (timerCounters[i].ctrl & TIMER_IEN) { /* raise timer interrupt */ cpuSetInterrupt(timerCounters[i].irq); } } else { timerCounters[i].counter -= CC_PER_INSTR; } } } void timerStart(int usec, void (*callback)(int param), int param) { Timer *timer; Timer *p; if (freeTimers == NULL) { error("out of timers"); } timer = freeTimers; freeTimers = timer->next; timer->alarm = currentTime + usec * CC_PER_USEC; timer->callback = callback; timer->param = param; if (activeTimers == NULL || timer->alarm < activeTimers->alarm) { /* link into front of active timers queue */ timer->next = activeTimers; activeTimers = timer; } else { /* link elsewhere into active timers queue */ p = activeTimers; while (p->next != NULL && p->next->alarm <= timer->alarm) { p = p->next; } timer->next = p->next; p->next = timer; } } void timerReset(void) { Timer *timer; int i; cPrintf("Resetting Timer...\n"); while (activeTimers != NULL) { timer = activeTimers; activeTimers = timer->next; timer->next = freeTimers; freeTimers = timer; } for (i = 0; i < NUMBER_TMRCNT; i++) { timerCounters[i].ctrl = 0x00000000; timerCounters[i].divisor = 0xFFFFFFFF; timerCounters[i].counter = 0xFFFFFFFF; timerCounters[i].irq = IRQ_TIMER_0 + i; } } void timerInit(void) { Timer *timer; int i; for (i = 0; i < NUMBER_TIMERS; i++) { timer = malloc(sizeof(Timer)); if (timer == NULL) { error("cannot allocate simulation timers"); } timer->next = freeTimers; freeTimers = timer; } timerReset(); } void timerExit(void) { Timer *timer; while (activeTimers != NULL) { timer = activeTimers; activeTimers = timer->next; timer->next = freeTimers; freeTimers = timer; } while (freeTimers != NULL) { timer = freeTimers; freeTimers = timer->next; free(timer); } }
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