3字节除以2字节商为三字节.txt

来自「共有 45 个程序源码」· 文本 代码 · 共 49 行

;  *** 三字节除以双字节,除数放R4\R5中R5为高位 
; ***  A\R1\R2\R4\R5  MOV  R4,TVNUM      MOV  R5,TVNUM+1
DIV3D2:  MOV  40H,#00H
         MOV  41H,#00H
     MOV  42H,#00H ; 46h47h48h为被除数,R4R5是除数,40h41h为余数,42h43h44h为商
         MOV  43H,#00H                 ; 低位   高        低 高                    低位   高
         MOV  44H,#00H
 DSTA:   MOV  R7,#18H
  DCA:   CLR  C
         MOV  A,46H
         RLC  A
         MOV  46H,A
         MOV  A,47H
         RLC  A
         MOV  47H,A
         MOV  A,48H
         RLC  A
         MOV  48H,A
          MOV  A,40H
          RLC  A
          MOV  40H,A
          MOV  A,41H
          RLC  A
          MOV  41H,A
          MOV  A,42H
          RLC  A
          MOV  42H,A
          MOV  A,43H
          RLC  A
          MOV  43H,A
          MOV  A,44H
          RLC  A
          MOV  44H,A
          CLR  C
          MOV  A,40H
          SUBB  A,R4
          MOV  R1,A
          MOV  A,41H
          SUBB  A,R5
          MOV  R2,A
          JC  DCB
          INC  42H
          MOV  A,R1
          MOV  40H,A
          MOV  A,R2
          MOV  41H,A
  DCB:   DJNZ  R7,DCA                  ; 结果在42H/43H/44H中
         RET