subb22.asm

通过调试的有用的单片机控制程序

;被减数-减数可能为补码形式
;所以最后可能是负数
ORG     0000H
SUBB22JH        DATA    40H     ;
SUBB22JL        DATA    41H
SUBB22BJL       DATA    43H     ;
SUBB22BJH       DATA    42H
SUBB22: CLR     C
        MOV     A,SUBB22BJL
        SUBB    A,SUBB22JL
        MOV     SUBB22BJL,A
        JNC      SUBB22N
        DEC     SUBB22BJH
SUBB22N:MOV     A,SUBB22BJH
        SUBB    A,SUBB22JH
        MOV     SUBB22BJH,A
        SJMP    $
        END