Compute N factorial
N! = N * (N-1)*(N-2)*...*2*1; 0! = 1 and 1!=1
addi $v0,$0,1 # Initialize
add $s0,$a0,$0 # Move argument
Loop: addi $s1,$s0,-1 # Reduce arg and move
beq $s1,$0,Done # Exit if we’re finished
mult $v0,$v0,$s0 # Multiply next term
addi $s0,$s0,-1 # Find the next term
j Loop # Continue until done