51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
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//#resource "astrocade.inc"
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#include "aclib.h"
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//#link "aclib.s"
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#include "acbios.h"
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//#link "acbios.s"
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//#link "hdr_autostart.s"
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#include <stdlib.h>
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#include <string.h>
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#pragma opt_code_speed
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// we have a special interrupt handler that sets
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// palette colors every 4 lines
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byte linenum = 0;
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void inthandler(void) __interrupt {
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byte i = linenum;
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hw_col0l = i;
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hw_col1l = i+1;
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hw_col2l = i+2;
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hw_col3l = i+3;
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i += 4;
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if (i > 200) i = 0;
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hw_inlin = i;
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linenum = i;
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}
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// pointer to the interrupt handler
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const t_interrupt_handler const intvector = &inthandler;
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// patterns to fill each 4-line scanline group
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const byte FILLPATS[4] = { 0x00, 0x55, 0xaa, 0xff };
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void main(void) {
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// fill screen with colors 0-3 every 4 scanlines
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for (byte i=0; i<89; i++) {
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memset(&vidmem[i], FILLPATS[i&3], 40);
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}
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// set our custom interrupt vector
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set_interrupt_vector(&intvector);
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// set screen height
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// set horizontal color split (position / 4)
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// set interrupt status (on)
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SYS_SETOUT(89*2, 20, 0x8);
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// infinite loop
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// let the interrupt handler do the work
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while (1) ;
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}
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