求用汇编语言编写拆字程序

ORG 0000H

AJMP MAIN

ORG 0100H

MAIN: MOV DPTR,#4000H

MOVX A,@DPTR

MOV B,A (4000H)

SWAP A 交换

ANL A,#0FH 屏蔽高位

INC DPTR

MOVX @DPTR,A送4001H

INC DPTR

MOV A,B

ANLA,#0FH (4000)内容屏蔽高位

MOVX @DPTR,A 送4002H

SJMP $

END

char xdata* ptr

char i

i = 0x12

ptr = 0x2000

*ptr = i //对2000H赋值

i = *ptr //从2000H取值

ptr=0x2001

*ptr = i&0xf0//2001h放高半字节

ptr++

*ptr = i&0x0f//2002h放低半字节

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