78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
#include <stddef.h>
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#include <stdint.h>
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#include <lib/stream.h>
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#define VGA_WIDTH 80
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#define VGA_HEIGHT 25
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#define VGA_MEMORY (0xB8000 + 0xC0000000)
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enum vga_color {
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VGA_COLOR_BLACK = 0,
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VGA_COLOR_BLUE = 1,
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VGA_COLOR_GREEN = 2,
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VGA_COLOR_CYAN = 3,
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VGA_COLOR_RED = 4,
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VGA_COLOR_MAGENTA = 5,
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VGA_COLOR_BROWN = 6,
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VGA_COLOR_LIGHT_GREY = 7,
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VGA_COLOR_DARK_GREY = 8,
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VGA_COLOR_LIGHT_BLUE = 9,
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VGA_COLOR_LIGHT_GREEN = 10,
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VGA_COLOR_LIGHT_CYAN = 11,
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VGA_COLOR_LIGHT_RED = 12,
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VGA_COLOR_LIGHT_MAGENTA = 13,
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VGA_COLOR_LIGHT_BROWN = 14,
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VGA_COLOR_WHITE = 15,
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};
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static size_t terminal_row;
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static size_t terminal_column;
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static uint8_t terminal_color;
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static uint16_t* terminal_buffer = (uint16_t*)VGA_MEMORY;
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static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
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{
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return fg | bg << 4;
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}
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static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
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{
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return (uint16_t) uc | (uint16_t) color << 8;
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}
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void vga_init() {
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terminal_row = 0;
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terminal_column = 0;
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terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
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for (size_t y = 0; y < VGA_HEIGHT; y++) {
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index = y * VGA_WIDTH + x;
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terminal_buffer[index] = vga_entry(' ', terminal_color);
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}
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}
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}
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void vga_putchar(char c) {
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if (c == '\n') {
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terminal_row++;
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terminal_column = 0;
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return;
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}
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if (c == '\t') {
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for (int i = 0; i < 4; i++) {
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vga_putchar(' ');
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}
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return;
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}
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const size_t index = terminal_row * VGA_WIDTH + terminal_column;
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terminal_buffer[index] = vga_entry(c, terminal_color);
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if (++terminal_column == VGA_WIDTH) {
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terminal_column = 0;
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if (++terminal_row == VGA_HEIGHT)
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terminal_row = 0;
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}
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} |