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8bitworkshop/presets/c64/test_setirq.c
2023-11-29 12:51:42 -06:00

51 lines
1.1 KiB
C

#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <peekpoke.h>
#include <string.h>
#include <c64.h>
#include <cbm_petscii_charmap.h>
#include "common.h"
//#link "common.c"
#include <6502.h>
#include <setjmp.h>
char interrupt_handler() {
// only needed if CIA interupts are still active
if (!(VIC.irr & VIC_IRR_IRST)) return IRQ_NOT_HANDLED;
// change colors so we can see where the IRQ fired
VIC.bgcolor0++;
VIC.bordercolor++;
// reading VIC.rasterline returns the current line
// setting it changes the line where the IRQ fires
if (VIC.rasterline >= 245) {
VIC.rasterline = 40;
} else {
VIC.rasterline = 245;
}
// acknowledge VIC raster interrupt (bit 0)
VIC.irr = 1;
// change colors back to where they were
VIC.bgcolor0--;
VIC.bordercolor--;
return IRQ_HANDLED;
}
void main(void) {
clrscr();
printf("\nHello World!\n");
// set interrupt routine
set_irq(interrupt_handler, (void*)0x9f00, 0x100);
// disable CIA interrupt, activate VIC interrupt
set_raster_irq(255);
while (1) {
printf("%d ", VIC.rasterline);
}
}