MSP430-Digital Input

digital input using the P1.3 (pull down resistor required)

.include "msp430g2x31.inc"
org 0xf800
mov.w #(WDTPW|WDTHOLD), &WDTCTL
CLR.B P1OUT
CLR R5
mov.b #0x41, &P1DIR
L1:   MOV.b &P1IN,  r5
      AND.b #0x8,r5
      tst r5
      JZ L1
      mov.b #0x41, &P1OUT
L3:   jmp L3
org 0xfffe
dw 0xf800