/*?
?*?Architecture?Lab:?Part?A?
?*?
?*?High?level?specs?for?the?functions?that?the?students?will?rewrite
?*?in?Y86?assembly?language
?*/

/*?$begin?examples?*/
/*?linked?list?element?*/
typedef?struct?ELE?{
????int?val;
????struct?ELE?*next;
}?*list_ptr;

/*?sum_list?-?Sum?the?elements?of?a?linked?list?*/
int?sum_list（list_ptr?ls）
{
????int?val?=?0;
????while?（ls）?{
	val?+=?ls->val;
	ls?=?ls->next;
????}
????return?val;
}

/*?rsum_list?-?Recursive?version?of?sum_list?*/
int?rsum_list（list_ptr?ls）
{
????if?（!ls）
	return?0;
????else?{
	int?val?=?ls->val;
	int?rest?=?rsum_list（ls->next）;
	return?val?+?rest;
????}
}

/*?copy_block?-?Copy?src?to?dest?and?return?xor?checksum?of?src?*/
int?copy_block（int?*src?int?*dest?int?len）
{
????int?result?=?0;
????while?（len?>?0）?{
	int?val?=?*src++;
	*dest++?=?val;
	result?^=?val;
	len--;
????}
????return?result;
}
/*?$end?examples?*/