msp430 i/o and interrupts: led state track button press on launchpad

interrupt.c

#include <msp430.h>

#define interrupt(x) void __attribute__((interrupt (x)))

interrupt(PORT1_VECTOR) isr() {
	P1OUT ^= BIT6 | BIT0; // toggle

	P1IES ^= BIT3; // change edge
	P1IFG = 0x00;
}

int main() {
	WDTCTL = WDTPW + WDTHOLD;

	P1DIR = BIT6 | BIT0;
	P1OUT = BIT3;
	P1REN = BIT3;

	P1IES = BIT3;
	P1IE  = BIT3; 	// PIN1.3
	P1IFG = 0x00;

	__enable_interrupt();
	for (;;) {}
	return 0;
}