EM78系列单片机的子程序

                  mov  0x24,a
                  swapa 0x21
                  and  a,@0x0f
                  mov  0x25,a  BCD码展开后存于0X22,0X23,0X24,0X25
                  mov  a,0x25,  0X25为最高位
                  mov  0x30,a
                  mov  a,@0x0  多字节加法高位为0
                  mov  0x31,a
                  mov  a,0x24
                  mov  0x32,a
                  call  a_b  调子程
                  mov  a,0x23
                  mov  0x32,a
                  call  a_b
                  mov  a,0x22
                  mov  0x32,a
                  call  a_b
                  self:   jmp  self

                  a_b:
                  mov  a,@0x0  0X34,0X35存储中间结果
                  mov  0x34,a
                  mov  0x35,a
                  mov  a,@0x0a  实现乘10
                  mov  0x33,a
                  a1:   mov  a,0x35  两字节二进制加法,在本例中高字节肯定无进位
                  add  a,0x31
                  mov  0x35,a
                  mov  a,0x34
                  add  a,0x30
                  mov  0x34,a
                  jbc  0x03,0
                  inc  0x35
                  djz  0x33
                  jmp  a1
                  mov  a,0x32
                  add  0x34,a
                  jbc  0x03,0
                  inc  0x35
                  mov  a,0x34
                  mov  0x30,a
                  mov  a,0x35
                  mov  0x31,a
                  ret
                  eop

                  七 二进制数转换为BCD码
                   本例为单字节二进制数(0X20)转换为非压缩BCD码,存在0X25,0X24,0X23中,0X25为百位,0X23为个位。
                  main: mov  a,@0xa4  赋值
                  mov  0x20,a
                  mov  0x21,a
                  mov  0x22,a
                  mov  a,@0x0  0x23,0x24,0x25单元清0
                  mov  0x23,a
                  mov  0x24,a
                  mov  0x25,a
                  mov  a,@0x64  对100的个数计数
                  mov  0x26,a
                  mov  a,@0x25  百位存在0x25中
                  mov  0x04,a
                  call  a0   调计数子程
                  mov  a,@0x0a  对10的个数计数
                  mov  0x26,a

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本文关键字：单片机  子程序  义隆单片机，单片机-工控设备 - 义隆单片机