loop:    DECI    num,d
         LDA     num,d
         ADDA    sum,d
         STA     sum,d
         LDA     counter,d
         ADDA    1,i
         STA     counter,d
         BREQ 0x00,x   quit        ;ERROR: Comment expected following instruction.
         BR      loop
quit:    DECO    sum,d
         STOP
sum:     .WORD   0x0000
num:     .BLOCK  2
counter: .WORD   0x0000
         .END