em không biên dịch được file này
 

list p = 16f84a
#include p16f84a.inc

x1 = 0x0c
x2 = x1+1
x3 = x2+1

status = 0x03
trisa = 0x85
trisb = 0x86
porta = 0x05
portb = 0x06

goto main

delay_
movwf x3
delay_1
decsfz x3,1
goto delay_1

return

main

movlw 0x20
movwf x2
movwf x1
bsf status,5
movlw 0xff
movwf trisb
movlw 0x00
movwf trisa
bcf status,5

here

bsf porta,0
nop
nop
bcf portb,0
goto here
movlw 0x25
movwf x2
movwf x1

goto main

end