78 lines
1.6 KiB
C
78 lines
1.6 KiB
C
/* ------------------------------------------------------------------------
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System : Manx Aztec C65 Version 3.2b
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MS-DOS cross-development environment
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Platform : Apple IIe 128K PRODOS 8
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Program : dmonplot.c
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Description : G2 Library Routine
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Double Hi-Res 560 x 192 x monochrome plot routine
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Written by : Bill Buckels
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Date Written : January 2013
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Revision : 1.0 First Release
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Licence : You may use this routine for whatever you wish as long
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as you agree that Bill Buckels has no warranty or
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liability obligations whatsoever from said use.
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------------------------------------------------------------------------ */
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extern unsigned DHRB[];
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extern unsigned char dhbmono[];
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extern unsigned char dhwmono[];
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int dhmonoplot(x,y1,y2,drawcolor)
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int x, y1, y2, drawcolor;
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{
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int y, xoff, pixel, aux = 1;
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unsigned char *ptr;
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#asm
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sta $c054 ; MAIN MEM
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#endasm
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/* swap coordinates if out of order */
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if (y1 > y2) {
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y = y1;
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y1 = y2;
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y2 = y;
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}
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/* allow bi-directional scanline wrap */
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if (x < 0) x+= 560;
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if (x > 559) x-=560;
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if (x < 0 || x > 559 || y1 < 0 || y2 > 191)return 0;
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pixel = (x%14);
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if (pixel > 6) {
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pixel -= 7;
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}
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else {
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#asm
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sta $c055 ; AUX MEM
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#endasm
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}
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xoff = x/14;
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y2++;
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for (y = y1; y < y2; y++) {
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ptr = (unsigned char *) (DHRB[y] + xoff);
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if (drawcolor != 0) {
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/* white */
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*ptr = *ptr | dhwmono[pixel]; /* inclusive OR */
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}
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else {
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/* black */
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*ptr = *ptr & dhbmono[pixel]; /* bitwise AND */
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}
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}
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/* reset to main memory */
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#asm
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sta $c054 ; MAIN MEM
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#endasm
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return 0;
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}
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