61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
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#include <conio.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <peekpoke.h>
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#include <string.h>
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#include <c64.h>
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#include <cbm_petscii_charmap.h>
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#include "common.h"
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//#link "common.c"
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#include <6502.h>
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#include <setjmp.h>
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char interrupt_handler() {
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// only needed if CIA interupts are still active
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if (!(VIC.irr & VIC_IRR_IRST)) return IRQ_NOT_HANDLED;
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// change colors so we can see where the IRQ fired
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VIC.bgcolor0++;
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VIC.bordercolor++;
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// reading VIC.rasterline returns the current line
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// setting it changes the line where the IRQ fires
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if (VIC.rasterline >= 245) {
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VIC.rasterline = 40;
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} else {
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VIC.rasterline = 245;
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}
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// acknowledge VIC raster interrupt (bit 0)
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VIC.irr = 1;
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// change colors back to where they were
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VIC.bgcolor0--;
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VIC.bordercolor--;
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return IRQ_HANDLED;
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}
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void set_frame_irq(char scanline) {
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// deactivate CIA interrupts (keyboard, etc)
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CIA1.icr = 0x7f;
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// set raster line for interrupt
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VIC.ctrl1 &= 0x7f; // clear raster line bit 8
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VIC.rasterline = scanline;
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// activate VIC raster interrupts
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VIC.imr = 1;
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}
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void main(void) {
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clrscr();
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printf("\nHello World!\n");
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// set interrupt routine
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set_irq(interrupt_handler, (void*)0x9f00, 0x100);
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// disable CIA interrupt, activate VIC interrupt
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set_frame_irq(255);
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while (1) {
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printf("%d ", VIC.rasterline);
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}
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}
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