Bulls & Cows in Assembler

The goal of this program is to find the 4-different digit number (without leading zeros) from user. The rules of game are following: user chooses any number, for example 4721, then program gives the first variant: for example 9732. The correct answer for the variant will be: 1 bull and 1 cow, meaning that in that variant one digit presents in correct number and is in the right place (it is about 7). The cow here is 2, because it presents in correct number, but isn't in the right place. Only knowing this information, for a number of tries program finds out the correct number. It's very interesting, try to play it with your friends!