40 lines
No EOL
1 KiB
C
40 lines
No EOL
1 KiB
C
#include <stdbool.h>
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#include <stdint.h>
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#define VGA_COLUMNS 80
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#define VGA_START (uint16_t *)0x000b8000
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#define VGA_END (VGA_START + VGA_COLUMNS * 25)
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static uint16_t *cursor = VGA_START;
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static uint16_t mask;
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void vga_set_color(uint8_t new_color) {
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mask = new_color << 8;
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}
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static void vga_scroll() {
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for (uint32_t *i = (uint32_t *)VGA_START; i < (uint32_t *)(VGA_END - VGA_COLUMNS); ++i)
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*i = *(i + VGA_COLUMNS / 2);
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uint32_t f = (mask | (uint8_t)' ') * 0x00010001;
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for (uint32_t *i = (uint32_t *)(VGA_END - VGA_COLUMNS); i < (uint32_t *)VGA_END; ++i)
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*i = f;
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cursor -= VGA_COLUMNS;
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}
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void vga_blank() {
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uint32_t f = (mask | (uint8_t)' ') * 0x00010001;
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uint32_t *p = (uint32_t *)VGA_START;
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while (p < (uint32_t *)VGA_END)
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*p++ = f;
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cursor = VGA_START;
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}
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void vga_printch(char ch) {
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if (ch == '\n')
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cursor = ((cursor - VGA_START) / VGA_COLUMNS + 1) * VGA_COLUMNS + VGA_START;
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else if (ch == '\b')
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*--cursor = mask | ' ';
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else
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*cursor++ = mask | (uint8_t)ch;
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if (cursor == VGA_END)
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vga_scroll();
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} |