mirror of
https://gitlab.com/camelot/kickc.git
synced 2024-06-02 00:41:42 +00:00
51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
// A raster IRQ that opens the top/bottom border.
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#include <c64.h>
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char* const GHOST_BYTE = (char*)0x3fff;
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void main() {
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*GHOST_BYTE = 0;
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asm { sei }
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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 0xfa
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VICII->CONTROL1 &= 0x7f;
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VICII->RASTER = 0xfa;
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// Enable Raster Interrupt
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VICII->IRQ_ENABLE = IRQ_RASTER;
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// Set the IRQ routine
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*HARDWARE_IRQ = &irq_bottom_1;
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// no kernal or BASIC rom visible
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*PROCPORT_DDR = PROCPORT_DDR_MEMORY_MASK;
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*PROCPORT = PROCPORT_RAM_IO;
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asm { cli }
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// Loop
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for (;;) ;
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}
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// Interrupt Routine 1
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__interrupt(hardware_clobber) void irq_bottom_1() {
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VICII->BORDER_COLOR = WHITE;
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// Set screen height to 24 lines - this is done after the border should have started drawing - so it wont start
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VICII->CONTROL1 &= (0xff^VICII_RSEL);
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// Acknowledge the IRQ
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VICII->IRQ_STATUS = IRQ_RASTER;
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// Trigger IRQ 2 at line 0xfd
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VICII->RASTER = 0xfd;
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*HARDWARE_IRQ = &irq_bottom_2;
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VICII->BORDER_COLOR = RED;
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}
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// Interrupt Routine 2
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__interrupt(hardware_clobber) void irq_bottom_2() {
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VICII->BORDER_COLOR = WHITE;
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// Set screen height back to 25 lines (preparing for the next screen)
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VICII->CONTROL1 |= VICII_RSEL;
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// Acknowledge the IRQ
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VICII->IRQ_STATUS = IRQ_RASTER;
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// Trigger IRQ 1 at line 0xfa
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VICII->RASTER = 0xfa;
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*HARDWARE_IRQ = &irq_bottom_1;
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VICII->BORDER_COLOR = RED;
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}
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