VGA_SCREEN
buf = VGA_SCREEN + x + y * VGA_TEXT_COLS;
src = VGA_SCREEN + x + y * VGA_TEXT_COLS;
VGA_SCREEN[row * VGA_TEXT_COLS + col] = (cons_color << 8) | c;
VGA_SCREEN[i] = VGA_SCREEN[i + VGA_TEXT_COLS];