Rock, paper, scissors referee

Referee one round of rock, paper, scissors. The input holds two moves, player 1's and then player 2's, each written as a number: 0 for rock, 1 for paper, 2 for scissors. Paper covers rock, scissors cut paper, and rock breaks scissors.

Print exactly one line:

• player 1 wins or player 2 wins
• draw when both players pick the same move
• invalid move when either number is outside 0 to 2; then main returns 1 instead of 0, so whoever ran the program can tell it failed

The starter reads both moves into p1_r and p2_r and holds every message you need. Hint: write out player 1's move minus player 2's for all nine rounds. Only five different gaps turn up, and each one always means the same result.

What is checked

• with the input 1 0 the program prints player 1 wins and returns 0
• the decisions are made with cmpCompares Rn with op2 by subtracting: sets the NZCV flags and throws the result away. Same as SUBS with the zero register as the destination.
• the checker also referees rounds you do not see: every winner, a draw, and moves just outside the range