70 lines
1.5 KiB
C
70 lines
1.5 KiB
C
// fether os kernel.
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#include <stddef.h>
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#include <stdint.h>
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// protecting compilation.
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#if defined(__linux__)
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#error "You should compile all with a cross-compiler. See project wiki."
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#elif !defined(__amd64__)
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#error "This is an 32bit\64bit kernel. Please use i386 or amd64 target."
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#elif !defined(__i386__)
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#error "This is an 32bit\64bit kernel. Please use i386 or amd64 target."
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#endif
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volatile uint16_t* vga_buffer = (uint16_t*)0xB8000; // defining VGA text mode.
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// vga(2) settings
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const int VGA_COLS = 80;
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const int VGA_ROWS = 25;
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// terminal settings
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int term_col = 0;
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int term_row = 0;
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uint8_t term_color = 0x0F;
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// clearing the terminal
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void term_init() {
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for(int col = 0; col < VGA_COLS; col++) {
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for(int row = 0; row < VGA_ROWS; row++) {
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const size_t index = (VGA_COLS * row) + col;
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vga_buffer[index] = ((uint16_t)term_color << 8) | ' ';
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}
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}
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}
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void term_put(char c) {
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switch(c) {
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case '\n': // newline implemintation
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{
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term_col = 0;
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term_row++;
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break;
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}
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default: // if char doesn't match any special symbol
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{
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const size_t index = (VGA_COLS * term_row) + term_col;
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vga_buffer[index] = ((uint16_t)term_color << 8) | c;
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break;
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}
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}
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if(term_col >= VGA_COLS) {
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term_col = 0;
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term_row++;
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}
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if(term_row >= VGA_ROWS) {
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term_col = 0;
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term_row = 0;
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}
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}
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void term_print(const char* str) { for(size_t i = 0; str[i] != '\0'; i++) { term_put(str[i]); } }
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void kmain() {
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term_init();
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term_print("Kernel loaded.\nFether.");
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}
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