ORG 00H
;---------------------------
SETUP:
  MOV P0,#00H
BUTTON:
  JNB P1.0,THUAN
  JNB P1.1,NGUOC
JMP BUTTON
;---------------------------
THUAN:
  JNB P1.0,$
  MOV A,#00000001B
  MOV R0,#8
L1:
  JNB P1.1,NGUOC
  MOV P0,A
  CALL DELAY
  RL A
  DJNZ R0,L1
  MOV R0,#0
  JMP THUAN
;---------------------------
NGUOC:
  JNB P1.1,$
  MOV A,#10000000B
  MOV R1,#8
L2:
  JNB P1.0,THUAN
  MOV P0,A
  CALL DELAY
  RR A
  DJNZ R1,L2
  MOV R1,#0
  JMP NGUOC
;---------------------------
DELAY:
  MOV TMOD,#01H
  MOV R2,#10
LAP:
  JNB P1.1,NGUOC
  JNB P1.0,THUAN
  MOV TH0,#HIGH(-50000)
  MOV TL0,#LOW(-50000)
  SETB TR0
  JNB TF0,$
  CLR TR0
  CLR TF0
  DJNZ R2,LAP
RET 
END