void interrupt_fixup_int_clk(interrupt_cpu_status_t *cs, CLOCK cpu_clk,
CLOCK *int_clk)
{
unsigned int num_cycles_left = 0, last_num_cycles_left = 0, num_dma;
unsigned int cycles_left_to_trigger_irq =
(OPINFO_DELAYS_INTERRUPT(*cs->last_opcode_info_ptr) ? 2 : 1);
CLOCK last_start_clk = CLOCK_MAX;
#ifdef DEBUGIRQDMA
if (debug.maincpu_traceflg) {
unsigned int i;
log_debug("INTREQ %ld NUMWR %i", (long)cpu_clk,
maincpu_num_write_cycles());
for (i = 0; i < cs->num_dma_per_opcode; i++)
log_debug("%iCYLEFT %i STCLK %i", i, cs->num_cycles_left[i],
cs->dma_start_clk[i]);
}
#endif
num_dma = cs->num_dma_per_opcode;
while (num_dma != 0) {
num_dma--;
num_cycles_left = cs->num_cycles_left[num_dma];
if ((cs->dma_start_clk[num_dma] - 1) <= cpu_clk)
break;
last_num_cycles_left = num_cycles_left;
last_start_clk = cs->dma_start_clk[num_dma];
}
/* if the INTREQ happens between two CPU cycles, we have to interpolate */
if (num_cycles_left - last_num_cycles_left > last_start_clk - cpu_clk - 1)
num_cycles_left = last_num_cycles_left + last_start_clk - cpu_clk - 1;
#ifdef DEBUGIRQDMA
if (debug.maincpu_traceflg) {
log_debug("TAKENLEFT %i LASTSTOLENCYCLECLK %i", num_cycles_left,cs->last_stolen_cycles_clk);
}
#endif
*int_clk = cs->last_stolen_cycles_clk;
if (cs->num_dma_per_opcode > 0 && cs->dma_start_clk[0] > cpu_clk) {
/* interrupt was triggered before end of last opcode */
*int_clk -= (cs->dma_start_clk[0] - cpu_clk);
}
#ifdef DEBUGIRQDMA
if (debug.maincpu_traceflg) {
log_debug("INTCLK dma shifted %i (cs->dma_start_clk[0]=%i", *int_clk, cs->dma_start_clk[0]);
}
#endif
if (num_cycles_left >= cycles_left_to_trigger_irq)
*int_clk -= (cycles_left_to_trigger_irq + 1);
#ifdef DEBUGIRQDMA
if (debug.maincpu_traceflg) {
log_debug("INTCLK fixed %i", *int_clk);
}
#endif
}
/* Return nonzero if a pending IRQ should be dispatched now. This takes
account for the internal delays of the 6510, but does not actually check
the status of the IRQ line. */
inline static int interrupt_check_irq_delay(interrupt_cpu_status_t *cs,
CLOCK cpu_clk)
{
CLOCK irq_clk = cs->irq_clk + INTERRUPT_DELAY;
/* Branch instructions delay IRQs and NMI by one cycle if branch
is taken with no page boundary crossing. */
if (OPINFO_DELAYS_INTERRUPT(*cs->last_opcode_info_ptr)) {
irq_clk++;
}
/* If an opcode changes the I flag from 1 to 0, the 6510 needs
one more opcode before it triggers the IRQ routine. */
if (cpu_clk >= irq_clk) {
if (!OPINFO_ENABLES_IRQ(*cs->last_opcode_info_ptr)) {
return 1;
} else {
cs->global_pending_int |= IK_IRQPEND;
}
}
return 0;
}
void interrupt_fixup_int_clk(interrupt_cpu_status_t *cs, CLOCK cpu_clk,
CLOCK *int_clk)
{
unsigned int num_cycles_left = 0, last_num_cycles_left = 0, num_dma;
unsigned int cycles_left_to_trigger_irq =
(OPINFO_DELAYS_INTERRUPT(*cs->last_opcode_info_ptr) ? 2 : 1);
CLOCK last_start_clk = CLOCK_MAX;
/*
{
unsigned int i;
log_debug("INTREQ %ld NUMWR %i", (long)cpu_clk,
maincpu_num_write_cycles());
for (i = 0; i < cs->num_dma_per_opcode; i++)
log_debug("%iCYLEFT %i STCLK %i", i, cs->num_cycles_left[i],
cs->dma_start_clk[i]);
}
*/
num_dma = cs->num_dma_per_opcode;
while (num_dma != 0) {
num_dma--;
num_cycles_left = cs->num_cycles_left[num_dma];
if ((cs->dma_start_clk[num_dma] - 1) <= cpu_clk)
break;
last_num_cycles_left = num_cycles_left;
last_start_clk = cs->dma_start_clk[num_dma];
}
/* if the INTREQ happens between two CPU cycles, we have to interpolate */
if (num_cycles_left - last_num_cycles_left > last_start_clk - cpu_clk - 1)
num_cycles_left = last_num_cycles_left + last_start_clk - cpu_clk - 1;
/*log_debug("TAKENLEFT %i", num_cycles_left);*/
*int_clk = cs->last_stolen_cycles_clk;
if (num_cycles_left >= cycles_left_to_trigger_irq)
*int_clk -= (cycles_left_to_trigger_irq + 1);
/*log_debug("INTCLK %i", *int_clk);*/
}
/* Return nonzero if a pending NMI should be dispatched now. This takes
account for the internal delays of the 6510, but does not actually check
the status of the NMI line. */
inline static int interrupt_check_nmi_delay(interrupt_cpu_status_t *cs,
CLOCK cpu_clk)
{
CLOCK nmi_clk = cs->nmi_clk + INTERRUPT_DELAY;
/* BRK (0x00) delays the NMI by one opcode. */
/* TODO DO_INTERRUPT sets last opcode to 0: can NMI occur right after IRQ? */
if (OPINFO_NUMBER(*cs->last_opcode_info_ptr) == 0x00) {
return 0;
}
/* Branch instructions delay IRQs and NMI by one cycle if branch
is taken with no page boundary crossing. */
if (OPINFO_DELAYS_INTERRUPT(*cs->last_opcode_info_ptr)) {
nmi_clk++;
}
if (cpu_clk >= nmi_clk) {
return 1;
}
return 0;
}
/* Asynchronously steal `num' cycles from the CPU, starting from cycle
`start_clk'. */
void dma_maincpu_steal_cycles(CLOCK start_clk, int num, CLOCK sub)
{
CLOCK irq_sub = 0;
CLOCK nmi_sub = 0;
unsigned int cycles_left_to_trigger_irq;
interrupt_cpu_status_t *cs = maincpu_int_status;
CLOCK dma_start;
if (num == 0)
return;
dma_start = start_clk + sub;
if (start_clk == cs->last_stolen_cycles_clk)
cs->num_last_stolen_cycles += num;
else
cs->num_last_stolen_cycles = num;
/*log_debug("START %i NUM %i SUB %i MAIN %i DMAST %i",
start_clk, num, sub, maincpu_clk, dma_start);*/
cs->num_cycles_left[cs->num_dma_per_opcode] = maincpu_clk - dma_start;
cs->dma_start_clk[cs->num_dma_per_opcode] = dma_start;
(cs->num_dma_per_opcode)++;
#ifdef DEBUG
if (debug.maincpu_traceflg)
debug_dma("VICII", start_clk, num);
#endif
cycles_left_to_trigger_irq =
(OPINFO_DELAYS_INTERRUPT(*cs->last_opcode_info_ptr) ? 2 : 1);
if (cs->irq_clk >= start_clk
&& dma_start == (maincpu_clk - cycles_left_to_trigger_irq)
&& cs->num_dma_per_opcode == 1) {
/*log_debug("DECR");*/
irq_sub = 1;
}
if (cs->nmi_clk >= start_clk
&& dma_start == (maincpu_clk - cycles_left_to_trigger_irq)
&& cs->num_dma_per_opcode == 1) {
/*log_debug("DECR");*/
nmi_sub = 1;
}
maincpu_clk += num;
cs->last_stolen_cycles_clk = dma_start + num;
/*log_debug("IRQCLK %i LASTSTOLEN %i",
cs->irq_clk, cs->last_stolen_cycles_clk);*/
if (cs->irq_clk > dma_start)
cs->irq_clk = cs->last_stolen_cycles_clk;
else
cs->irq_clk += num;
if (cs->nmi_clk > dma_start)
cs->nmi_clk = cs->last_stolen_cycles_clk;
else
cs->nmi_clk += num;
cs->irq_clk -= irq_sub;
cs->nmi_clk -= nmi_sub;
/*log_debug("NEWIRQCLK %i", cs->irq_clk);*/
}
