楼 主:zlin81819 2003年6月10日13:32

 [求助]这段程序完成的功能！
l154                 movlw    18h   ;  二进制转换bcd
                    movwf    13    ;   18h → f13
                    movf     0a, 0  ;   fa → w
                    movwf    0d     ;   fa → f
                    movf     0b, 0  ;   fb → w
                    movwf    0e     ;   fb →fe
                    movf     0c, 0  ;   fc → w
                    movwf    0f     ;   fc → ff
                    clrf     0a     ;   fa清0
                    clrf     0c     ;   fc清0
                    clrf    fsr    ;   f4清0
                    clrf    11     ;   f11清0
                    clrf    12     ;   f12清0
l161                 bcf     status, 0   ;  进位标志c清0
                    rlf     0f, 1   ;   ff左移1位 → ff
                    rlf     0e, 1   ;   fe左移1位 → fe
                    rlf     0d, 1   ;   fd左移1位 → fd
                    rlf     12, 1  ;   f12左移1位 → f12
                    rlf     11, 1  ;   f11左移1位 → f11
                    movf     8, 0  ;   f8 → w
                    subwf   11, 0  ;   f11-f8 → w
                    btfss    status, 2  ;  f11-f8=0时z=1,z=1跳
                    goto    l16d    ;
                    movf     9, 0   ;   f9 → w
                    subwf   12, 0    ;  f12-f9 → w
l16d                 btfss    status, 0   ;  进位标志c=1跳
                    goto     l176        ;
                    movf     9, 0       ;   f9 → w
                    subwf    12, 1      ;   f12-f9 → f12
                    btfss    status, 0   ;  f12>  f9, c=1跳
                    decf     11, 1     ;    f11-1 → f11
                    movf     8, 0     ;     f8 → w
                    subwf    11, 1    ;     f11-f8 → f11
                    bsf     status, 0   ;   进位标志位c置1
l176                 rlf     0c, 1  ;  fc左移1位 → fc
                    rlf     0b, 1  ;  fb左移1位 → fb
                    rlf     0a, 1  ;  fa左移1位 → fa
                    decfsz  13, 1 ;  f13-1 → f13 f13-1=0跳
                    goto    l161   ;                    goto    l108   ;
l108                 clrwdt
                    movf    16, 1       ;  f16 → f16
                    btfss    status, 2  ;   判断f16,f16=0,z=1,z=1跳
                    goto    l110         ;
                    movf    17, 1       ;  f17 → f17
                    btfss    status, 2  ;  f17=0,z=1跳
                    goto    l110
                    goto    l11d
l110                 bcf     status, 0  ;  进位标志c清0
                    rrf     16, 1      ;  f16右移1位 → f16
                    rrf     17, 1      ;  f17右移1位 → f17
                    bcf     status, 0  ;  进位标志c清0
                    rrf     0b, 1       ;  fb右移1位 → fb
                    rrf     0c, 1       ;  fc右移1位 → fc
                    bcf     status, 0  ;  进位标志c清0
                    movf    17, 0      ;  f17 → w
                    addwf   0c, 1       ;  f17+fc → fc
                    btfsc    status, 0  ;  进位标志c=0跳
                    incf    16, 1      ;  f16+1 → f16
                    movf    16, 0      ;  f16 → w
                    addwf   0b, 1       ;  f16+fb → fb
l11d                 movf    0b, 0       ;  fb → w
                    movwf   16         ;  fb → f16
                    movf    0c, 0       ;  fc → w
                    movwf   17         ;  fc → f17

讲讲f8.f9f11,f12,fa,fb,fc,f16,f17这几个寄存器的变化情况，