94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
// screen.c
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#include "../include/screen.h"
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#include "../include/string.h"
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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;
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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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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 terminal_initialize(void)
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{
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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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{
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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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{
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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(void)
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{
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for (size_t y = 0; y < VGA_HEIGHT - 1; y++) {
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index_from = (y + 1) * VGA_WIDTH + x;
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const size_t index_to = y * VGA_WIDTH + x;
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terminal_buffer[index_to] = terminal_buffer[index_from];
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}
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}
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
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terminal_buffer[index] = vga_entry(' ', terminal_color);
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}
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terminal_row = VGA_HEIGHT - 1;
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terminal_column = 0;
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}
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void terminal_putchar(char c)
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{
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if(c != '\n')
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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_scroll();
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}
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if(terminal_row >= VGA_HEIGHT){
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terminal_scroll();
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}
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if(c == '\n')
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{
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terminal_column = 0;
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terminal_row++;
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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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{
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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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{
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terminal_write(data, strlen(data));
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}
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