MOV $a0 9
     JAL @FIB
     END

     # COMPUTE THE A0th FIBONACCI NUMBER,
     # ASSUMING A0 IS >= 0
FIB: CMP $a0 1       # is A0 in a base case?
     JMP ?GT @REC    # if not, then skip
     MOV ?LE $rv $a0 # if A0 <= 1, return A0
     JMP $ra
REC: ADD $sp $sp -2  # allocate 2 slots on stack
     MST $ra 0($sp)  # backup RA
     MST $a0 1($sp)  # backup A0
     ADD $a0 $a0 -1  # setup recursive call
     JAL @FIB
     MLD $a0 1($sp)  # restore A0 
     MST $rv 1($sp)  # backup RV
     ADD $a0 $a0 -2  # setup recursive call
     JAL @FIB
     MLD $t0 1($sp)  # get 1st RV
     ADD $rv $rv $t0 # add together the 2 RVs
     MLD $ra 0($sp)  # restore RA
     ADD $sp $sp 2   # clean up the stack
     JMP $ra         # return