97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/*
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From OSDev Wiki:
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IMPORTANT NOTE: the VGA text mode (as well as the BIOS) is deprecated
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on newer machines, and UEFI only supports pixel buffers. For forward
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compatibility you might want to start with that. Ask GRUB to set up a
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framebuffer using appropriate Multiboot flags or call VESA VBE yourself. Unlike
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VGA text mode, a framebuffer has pixels, so you have to draw each glyph
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yourself.
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*/
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#include <vga.h>
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#include <string.h>
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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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static inline 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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static inline uint16_t vga_entry(unsigned char uc, int color) {
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return (uint16_t) uc | (uint16_t) color << 8;
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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_scroll() {
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if (terminal_row >= 25) {
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int i;
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for (i = 0; i < 24*80; i++)
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terminal_buffer[i] = terminal_buffer[i+80];
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for (i = 24*80; i < 25*80; i++)
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terminal_buffer[i] = ' ';
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terminal_row = 24;
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}
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}
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void terminal_delete_last_line() {
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int x, *ptr;
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for(x = 0; x < VGA_WIDTH * 2; x++) {
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ptr = (int*)0xB8000 + (VGA_WIDTH * 2) * (VGA_HEIGHT - 1) + x;
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*ptr = 0;
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}
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}
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void terminal_putchar(char c) {
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terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
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if (c != '\n') {
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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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for(int line = 1; line <= VGA_HEIGHT - 1; line++)
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terminal_scroll(line);
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terminal_delete_last_line();
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terminal_row = VGA_HEIGHT - 1;
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}
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}
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} else {
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terminal_row += 1;
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terminal_column = 0;
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}
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terminal_scroll();
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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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