.globl fac3

fac3:
        li    $t0, 1                 # check for base case
        bgt   $a0, $t0, recurse
        li    $v0, 1                 # if so, set return value
        jr    $ra                    #        and return

recurse:
        addi  $sp, $sp, -8           # make room on stack for
        sw    $ra, 4($sp)            #      return address, and
        sw    $a0, 0($sp)            #      N

        addi  $a0, $a0, -1           # calc N-1 for recursive call
        jal   fac3                   # calc (N-1)!
        lw    $t1, 0($sp)            # restore N from stack
        mul   $v0, $v0, $t1          # multiply (N-1)! by N

        lw    $ra, 4($sp)            # restore return address from stack
        addi  $sp, $sp, 8            #    and restore stack pointer
        jr    $ra                    #    and return