41 lines
739 B
C
41 lines
739 B
C
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#include "common.h"
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void raster_wait(byte line) {
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while (VIC.rasterline < line) ;
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}
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void wait_vblank(void) {
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raster_wait(250);
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}
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static byte VIC_BANK_PAGE[4] = {
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0xc0, 0x80, 0x40, 0x00
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};
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char* get_vic_bank_start() {
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return (char*)(VIC_BANK_PAGE[CIA2.pra & 3] << 8);
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}
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char* get_screen_memory() {
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return ((VIC.addr & 0xf0) << 6) + get_vic_bank_start();
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}
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#ifdef __CC65__
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char __fastcall__ poll_keyboard() {
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asm("jmp $f142");
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return __A__;
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}
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#endif
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void set_raster_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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