annotate src/vid.c @ 1:ebe5e0e44a9d
pretty much finished the code for article 1, might do minor adjustments though
| author |
John Tsiombikas <nuclear@member.fsf.org> |
| date |
Thu, 02 Dec 2010 08:45:41 +0200 |
| parents |
662ff2170531 |
| children |
86781ef20689 |
| rev |
line source |
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1 #include <string.h>
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2 #include "vid.h"
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3
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4 static uint16_t *vmem = (uint16_t*)0xb8000;
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5
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6 void clear_scr(int color)
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7 {
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8 memset(vmem, 0, WIDTH * HEIGHT * 2);
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9 }
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10
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11 void set_char(char c, int x, int y, int fg, int bg)
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12 {
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13 uint16_t attr = (fg & 0xf) | ((bg & 7) << 4);
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14 vmem[y * WIDTH + x] = (uint16_t)c | (attr << 8);
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15 }
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16
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17 void scroll_scr(void)
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18 {
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19 /* copy the second up to last text line, one line back, then
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20 * clear the last line.
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21 */
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22 memmove(vmem, vmem + WIDTH, WIDTH * (HEIGHT - 1) * 2);
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23 memset(vmem + WIDTH * (HEIGHT -1), 0, WIDTH * 2);
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24 }
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