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https://gitlab.com/camelot/kickc.git
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59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
// A minimal working raster IRQ
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typedef void (*IRQ_TYPE)(void);
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IRQ_TYPE* const KERNEL_IRQ = (IRQ_TYPE*)$0314;
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IRQ_TYPE* const HARDWARE_IRQ = (IRQ_TYPE*)$fffe;
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byte* const RASTER = (byte*)$d012;
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byte* const VICII_CONTROL1 = (byte*)$d011;
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byte* const IRQ_STATUS = (byte*)$d019;
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byte* const IRQ_ENABLE = (byte*)$d01a;
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const byte IRQ_RASTER = %00000001;
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const byte IRQ_COLLISION_BG = %00000010;
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const byte IRQ_COLLISION_SPRITE = %00000100;
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const byte IRQ_LIGHTPEN = %00001000;
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byte* const BG_COLOR = (byte*)$d020;
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byte* const FGCOL = (byte*)$d021;
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const byte WHITE = 1;
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const byte BLACK = 0;
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byte* const CIA1_INTERRUPT = (byte*)$dc0d;
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const byte CIA_INTERRUPT_CLEAR_ALL = $7f;
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// Processor port data direction register
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byte* const PROCPORT_DDR = (byte*)$00;
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// Mask for PROCESSOR_PORT_DDR which allows only memory configuration to be written
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const byte PROCPORT_DDR_MEMORY_MASK = %00000111;
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// Processor Port Register controlling RAM/ROM configuration and the datasette
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byte* const PROCPORT = (byte*)$01;
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// RAM in $A000, $E000 I/O in $D000
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const byte PROCPORT_RAM_IO = %00110101;
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// RAM in $A000, $E000 CHAR ROM in $D000
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void main() {
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asm { sei }
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// Disable kernal & basic
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*PROCPORT_DDR = PROCPORT_DDR_MEMORY_MASK;
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*PROCPORT = PROCPORT_RAM_IO;
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// Disable CIA 1 Timer IRQ
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*CIA1_INTERRUPT = CIA_INTERRUPT_CLEAR_ALL;
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// Set raster line to $100
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*VICII_CONTROL1 |=$80;
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*RASTER = $00;
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// Enable Raster Interrupt
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*IRQ_ENABLE = IRQ_RASTER;
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// Set the IRQ routine
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*HARDWARE_IRQ = &irq;
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asm { cli }
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while(true) {
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(*FGCOL)++;
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}
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}
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// Interrupt Routine
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__interrupt(hardware_all) void irq() {
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*BG_COLOR = WHITE;
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*BG_COLOR = BLACK;
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// Acknowledge the IRQ
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*IRQ_STATUS = IRQ_RASTER;
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} |