s4.asm

(1)完成键盘

; 移动 3000H --> 4000H, 256 字节

       mov   r0, #30h
       mov   r1, #00h
       mov   r2, #40h
       mov   r3, #00h

       mov   r7, #0
Loop:
       mov   dph, r0
       mov   dpl, r1
       movx  a, @dptr
       mov   dph, r2
       mov   dpl, r3
       movx  @dptr, a

       cjne  r1, #0ffh, Goon1
       inc   r0
Goon1:
       inc   r1

       cjne  r3, #0ffh, Goon2
       inc   r2
Goon2:
       inc   r3
       djnz  r7, Loop

       ljmp  $

       end