rem: memcpy((void *)origin, (void *)origin+2*COLUMNS, 2*(LINES-1)*COLUMNS);
add: memcpy((void *)origin, (void *)(origin + 2 * COLUMNS), 2 * (LINES - 1) * COLUMNS);
context: static void scrup(void){	unsigned long i;	// move the screen up one	memcpy((void *)origin, (void *)origin+2*COLUMNS, 2*(LINES-1)*COLUMNS);	// set the new position to the beginning of the last line	pos = origin + (LINES-1)*COLUMNS*2;	// clear the bottom line	for(i = pos; i < scr_end; i += 2) {		*(unsigned short *)i = 0x0720;	}}