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Implement timers from GBA.js implementation

This commit is contained in:
Jeffrey Pfau 2013-04-19 22:26:44 -07:00
parent 6087ad8c5f
commit 57dcbef030
2 changed files with 134 additions and 4 deletions
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126
src/gba/gba.c
View File

@ -9,6 +9,7 @@
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
enum {
@ -18,6 +19,7 @@ enum {
};
static void GBAProcessEvents(struct ARMBoard* board);
static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles);
static void GBAHitStub(struct ARMBoard* board, uint32_t opcode);
void GBAInit(struct GBA* gba) {
@ -39,6 +41,8 @@ void GBAInit(struct GBA* gba) {
GBAIOInit(gba);
memset(gba->timers, 0, sizeof(gba->timers));
gba->springIRQ = 0;
ARMReset(&gba->cpu);
@ -82,10 +86,128 @@ static void GBAProcessEvents(struct ARMBoard* board) {
nextEvent = testEvent;
}
testEvent = GBATimersProcessEvents(gbaBoard->p, cycles);
if (testEvent < nextEvent) {
nextEvent = testEvent;
}
board->cpu->cycles = 0;
board->cpu->nextEvent = nextEvent;
}
static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles) {
int32_t nextEvent = INT_MAX;
if (gba->timersEnabled) {
struct GBATimer* timer;
struct GBATimer* nextTimer;
timer = &gba->timers[0];
if (timer->enable) {
timer->nextEvent -= cycles;
if (timer->nextEvent <= 0) {
timer->nextEvent += timer->overflowInterval;
gba->memory.io[REG_TM0CNT_LO >> 1] = timer->reload;
timer->oldReload = timer->reload;
if (timer->doIrq) {
GBARaiseIRQ(gba, IRQ_TIMER0);
}
nextTimer = &gba->timers[1];
if (nextTimer->countUp) {
++gba->memory.io[REG_TM1CNT_LO >> 1];
if (!gba->memory.io[REG_TM1CNT_LO >> 1]) {
nextTimer->nextEvent = 0;
}
}
}
nextEvent = timer->nextEvent;
}
timer = &gba->timers[1];
if (timer->enable) {
timer->nextEvent -= cycles;
if (timer->nextEvent <= 0) {
timer->nextEvent += timer->overflowInterval;
gba->memory.io[REG_TM1CNT_LO >> 1] = timer->reload;
timer->oldReload = timer->reload;
if (timer->doIrq) {
GBARaiseIRQ(gba, IRQ_TIMER1);
}
if (timer->countUp) {
timer->nextEvent = INT_MAX;
}
nextTimer = &gba->timers[2];
if (nextTimer->countUp) {
++gba->memory.io[REG_TM2CNT_LO >> 1];
if (!gba->memory.io[REG_TM2CNT_LO >> 1]) {
nextTimer->nextEvent = 0;
}
}
}
if (timer->nextEvent < nextEvent) {
nextEvent = timer->nextEvent;
}
}
timer = &gba->timers[2];
if (timer->enable) {
timer->nextEvent -= cycles;
nextEvent = timer->nextEvent;
if (timer->nextEvent <= 0) {
timer->nextEvent += timer->overflowInterval;
gba->memory.io[REG_TM2CNT_LO >> 1] = timer->reload;
timer->oldReload = timer->reload;
if (timer->doIrq) {
GBARaiseIRQ(gba, IRQ_TIMER2);
}
if (timer->countUp) {
timer->nextEvent = INT_MAX;
}
nextTimer = &gba->timers[3];
if (nextTimer->countUp) {
++gba->memory.io[REG_TM3CNT_LO >> 1];
if (!gba->memory.io[REG_TM3CNT_LO >> 1]) {
nextTimer->nextEvent = 0;
}
}
}
if (timer->nextEvent < nextEvent) {
nextEvent = timer->nextEvent;
}
}
timer = &gba->timers[3];
if (timer->enable) {
timer->nextEvent -= cycles;
nextEvent = timer->nextEvent;
if (timer->nextEvent <= 0) {
timer->nextEvent += timer->overflowInterval;
gba->memory.io[REG_TM3CNT_LO >> 1] = timer->reload;
timer->oldReload = timer->reload;
if (timer->doIrq) {
GBARaiseIRQ(gba, IRQ_TIMER3);
}
if (timer->countUp) {
timer->nextEvent = INT_MAX;
}
}
if (timer->nextEvent < nextEvent) {
nextEvent = timer->nextEvent;
}
}
}
return nextEvent;
}
void GBAAttachDebugger(struct GBA* gba, struct ARMDebugger* debugger) {
ARMDebuggerInit(debugger, &gba->cpu);
gba->debugger = debugger;
@ -97,10 +219,6 @@ void GBALoadROM(struct GBA* gba, int fd) {
}
void GBAWriteIE(struct GBA* gba, uint16_t value) {
if (value & ((1 << IRQ_TIMER0) | (1 << IRQ_TIMER1) | (1 << IRQ_TIMER2) | (1 << IRQ_TIMER3))) {
GBALog(GBA_LOG_STUB, "Timer interrupts not implemented");
}
if (value & (1 << IRQ_SIO)) {
GBALog(GBA_LOG_STUB, "SIO interrupts not implemented");
}

12
src/gba/gba.h
View File

@ -46,6 +46,18 @@ struct GBA {
struct ARMDebugger* debugger;
int timersEnabled;
struct GBATimer {
uint16_t reload;
uint16_t oldReload;
int32_t nextEvent;
int32_t overflowInterval;
unsigned prescaleBits : 4;
unsigned countUp : 1;
unsigned doIrq : 1;
unsigned enable : 1;
} timers[4];
int springIRQ;
enum GBAError errno;