Merge pull request #390 from vintagepc/unaligned-PCINTs

Support for non-aligned PCINTs

Author: buserror

simavr/cores/sim_mega2560.h

@@ -102,7 +102,17 @@ const struct mcu_t {
 	AVR_IOPORT_DECLARE(f, 'F', F),
 	AVR_IOPORT_DECLARE(g, 'G', G),
 	AVR_IOPORT_DECLARE(h, 'H', H),
-	AVR_IOPORT_DECLARE(j, 'J', J),
+	.portj = {
+		.name = 'J', .r_port = PORTJ, .r_ddr = DDRJ, .r_pin = PINJ,
+		.pcint = {
+			 .enable = AVR_IO_REGBIT(PCICR, PCIE1),
+			 .raised = AVR_IO_REGBIT(PCIFR, PCIF1),
+			 .vector = PCINT1_vect,
+			 .mask = 0b11111110,
+			 .shift = -1
+		},
+		.r_pcint = PCMSK1,
+	},
 	AVR_IOPORT_DECLARE(k, 'K', K),
 	AVR_IOPORT_DECLARE(l, 'L', L),
 
@@ -353,7 +363,7 @@ const struct mcu_t {
 		.r_tcnt = TCNT2,
 		// asynchronous timer source bit.. if set, use 32khz frequency
 		.as2 = AVR_IO_REGBIT(ASSR, AS2),
-		
+
 		.overflow = {
 			 .enable = AVR_IO_REGBIT(TIMSK2, TOIE2),
 			 .raised = AVR_IO_REGBIT(TIFR2, TOV2),

simavr/sim/avr_ioport.c

@@ -153,7 +153,18 @@ avr_ioport_irq_notify(
 
 	if (p->r_pcint) {
 		// if the pcint bit is on, try to raise it
-		int raise = avr->data[p->r_pcint] & mask;
+		int raisedata = avr->data[p->r_pcint];
+		uint8_t uiRegMask = p->pcint.mask;
+		int8_t iShift = p->pcint.shift;
+		if (uiRegMask) // If mask is 0, do nothing (backwards compat)
+			raisedata &= uiRegMask; // Mask off
+
+		if (iShift>0) // Shift data if necessary for alignment.
+			raisedata <<= iShift;
+		else if (iShift<0)
+			raisedata >>= -iShift;
+
+		int raise = raisedata & mask;
 		if (raise)
 			avr_raise_interrupt(avr, &p->pcint);
 	}
@@ -279,4 +290,3 @@ void avr_ioport_init(avr_t * avr, avr_ioport_t * p)
 	avr_register_io_write(avr, p->r_pin, avr_ioport_pin_write, p);
 	avr_register_io_write(avr, p->r_ddr, avr_ioport_ddr_write, p);
 }
-

simavr/sim/sim_interrupts.h

@@ -42,6 +42,9 @@ typedef struct avr_int_vector_t {
 	avr_regbit_t 	enable;			// IO register index for the "interrupt enable" flag for this vector
 	avr_regbit_t 	raised;			// IO register index for the register where the "raised" flag is (optional)
 
+	uint8_t 		mask; // Mask for PCINTs. this is needed for chips like the 2560 where PCINT do not align with IRQs
+	int8_t 		shift;	// PCINT8 = E0, PCINT9-15 are on J0-J6. Shift shifts down (<0) or up (>0) for alignment with IRQ#.
+
 	// 'pending' IRQ, and 'running' status as signaled here
 	avr_irq_t		irq[AVR_INT_IRQ_COUNT];
 	uint8_t			pending : 1,	// 1 while scheduled in the fifo