MSP430G2553: clock system programming using interrupts

Hello everyone,

I am doing a program on clock system  of msp430g2553 using interrupt method but the code is not running.The code doesn't have any errors but there is no output.

The code is attached below:

#include "msp430g2553.h"

#ifndef TIMER0_A1_VECTOR
#define TIMER0_A1_VECTOR TIMERA1_VECTOR
#define TIMER0_A0_VECTOR TIMERA0_VECTOR
#endif

void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // watchdog timer setup

if (CALBC1_1MHZ ==0xFF || CALDCO_1MHZ == 0xFF)
{
while(1); // If cal constants erased,
} // trap CPU!!

BCSCTL1 = CALBC1_1MHZ; // Set range
DCOCTL = CALDCO_1MHZ; // Set DCO step + modulation

BCSCTL3 |= LFXT1S_2 + XCAP_3; // clock system setup

BCSCTL2 |= SELM_0 + DIVM_3;
IFG1 |=OFIFG;
_bis_SR_register(SCG0+SCG1+GIE);

}
#pragma vector=PORT1_VECTOR
__interrupt void port1(void)
{
//P1DIR = BIT0; // I/O setup
//P1OUT = 0;

while(1)
{
P1OUT = BIT0; // LED on
_delay_cycles(100);
P1OUT = 0; // LED off
_delay_cycles(5000);
}
}