138 lines
No EOL
3.1 KiB
C
138 lines
No EOL
3.1 KiB
C
#ifndef TERMINAL_C
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#define TERMINAL_C
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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static const size_t VGA_WIDTH = 80;
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static const size_t VGA_HEIGHT = 25;
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/* Hardware text mode color constants. */
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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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size_t terminal_row;
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size_t terminal_column;
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uint8_t terminal_color;
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uint16_t* terminal_buffer;
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uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) {
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return fg | bg << 4;
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}
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uint16_t vga_entry(unsigned char uc, uint8_t color) {
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return (uint16_t) uc | (uint16_t) color << 8;
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}
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size_t strlen(const char* str) {
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size_t len = 0;
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while (str[len])
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len++;
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return len;
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}
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void terminal_initialize(void) {
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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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terminal_buffer = (uint16_t*) 0xB8000;
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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 terminal_setcolor(uint8_t color) {
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terminal_color = color;
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}
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void terminal_putentryat(char c, uint8_t color, size_t x, size_t y) {
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const size_t index = y * VGA_WIDTH + x;
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terminal_buffer[index] = vga_entry(c, color);
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}
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void terminal_putchar(char c) {
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if (c == '\n') {
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terminal_column = 0;
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terminal_row++;
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return;
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}
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if (c == 0x08) {
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terminal_putentryat(' ', terminal_color, terminal_column, terminal_row);
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if (terminal_column == 0) {
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if(terminal_row != 0) {
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terminal_row--;
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terminal_column = VGA_WIDTH - 1;
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}
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} else {
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terminal_column--;
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}
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terminal_putentryat(' ', terminal_color, terminal_column, terminal_row);
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return;
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}
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terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
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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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}
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void terminal_write(const char* data, size_t size) {
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for (size_t i = 0; i < size; i++)
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terminal_putchar(data[i]);
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}
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void terminal_writestring(const char* data) {
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terminal_write(data, strlen(data));
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}
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char* itoa(unsigned int value, char* result, int base) {
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// check that the base if valid
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if (base < 2 || base > 36) { *result = '\0'; return result; }
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char* ptr = result, *ptr1 = result, tmp_char;
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int tmp_value;
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do {
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tmp_value = value;
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value /= base;
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*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
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} while ( value );
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*ptr-- = '\0';
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while(ptr1 < ptr) {
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tmp_char = *ptr;
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*ptr--= *ptr1;
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*ptr1++ = tmp_char;
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}
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return result;
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}
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void terminal_writeint(int number, int base) {
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char* result = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
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itoa(number, result, base);
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terminal_writestring(result);
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}
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#endif //TERMINAL_C
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