unsigned long processInterrupt(unsigned long intMask, unsigned short npc, unsigned long startTime, signed long cycleLimit) {
// known limitation: if the code uses ROM routines (e.g. register restore/return sequence) then we will
// be missing those cpu cycles in our calculation..
unsigned long originalDigiCount= sDigiCount;
if (isPsidDummyIrqVector()) {
// no point in trying to keep the stack consistent for a PSID
cpuReset();
}
// provide dummy return address - which we use to return from the emulation:
// in case of RTI (e.g. progs implementing $fffe/f vector directly) this will be used "as is".
// if some program was to return with "RTS" (e.g. legacy PSID) the address would be returned as $0001.
push(0); // addr high
push(0); // addr low
push(p); // processor status (processor would do this in case of interrupt...)
// only set pc and keep current stackpointer and registers in case player directly passes
// them between calls (see Look_sharp.sid)
pc= npc;
sProgramMode= intMask;
initCycleCount( (intMask == NMI_OFFSET_MASK) ? 7 : 0, startTime);
while (pc > 1 && ((cycleLimit <0) || (sCycles <cycleLimit)))
cpuParse();
sProgramMode= MAIN_OFFSET_MASK;
if (intMask == IRQ_OFFSET_MASK) {
sCurrentVolume= getmem(0xd418);
}
markSampleOrigin(intMask, startTime, originalDigiCount);
return sCycles;
}
static uint32_t processInterrupt(uint32_t intMask, uint16_t npc, uint32_t startTime, int32_t cycleLimit) {
// known limitation: if the code uses ROM routines calculation is flawed (see mock-up ROM routines).
uint16_t originalDigiCount= digiGetCount();
uint16_t originalDigiOverflowCount= digiGetOverflowCount();
sidResetVolumeChangeCount();
if (isPsidDummyIrqVector()) {
// no point in trying to keep the stack consistent for a PSID
cpuRegReset();
}
cpuResetToIrq(npc);
cpuSetProgramMode(intMask);
initCycleCount(intMask, startTime);
if (intMask == IRQ_OFFSET_MASK) {
vicSyncRasterIRQ();
// FIXME the cpu interrupt flag should also be set before starting the interrupt handler!
// but since no one seems to have missed it yet..
}
while (cpuPcIsValid() && ((cycleLimit <0) || (cpuCycles() <cycleLimit))) {
vicSimRasterline();
cpuParse();
}
cpuSetProgramMode(MAIN_OFFSET_MASK);
digiTagOrigin(intMask, startTime, originalDigiCount, originalDigiOverflowCount);
if (intMask == IRQ_OFFSET_MASK) _volUpdates+= sidGetNumberOfVolumeChanges(); // number of updates to the volume
return cpuCycles();
}
