Enabling and initialising interrupts in msp430f5438

#include"iomsp430.h"

#define headup P4OUT_bit.P4OUT_O

#define photoint P4OUT_bit.P4OUT_5

void main (void)

{

  WDTCTL = WDTPW + WDTHOLD;   // Stop watchdog timer

 P4DIR_bit.P4DIR_0 = 1;

 P4DIR_bit.P4DIR_5 = 1;


P1REN |= BIT2; // P1.2 Enable Pullup/Pulldown

P1OUT = BIT2;                                           // P1.2 pullup

P1IE |= BIT2;                                              // P1.2 interrupt enabled

 P1IES |= BIT2;                                          // P1.2 Hi/lo falling edge

P1IFG &= ~BIT2;                                       // P1.2 IFG cleared just in case

_EINT();

if (headup==1)

     {
        
                if (photoint ==1)
               
                    {
                        
                          steppermotor();

                     }


  else


    __bis_SR_register(LPM4_bits + GIE);     // LPM4 with interrupts enabled

    __no_operation();

   }


void steppermotor(void)

P4DIR |= 0x40; // Set P4.5 to output direction

 for (;;)
{
 P4OUT ^ = 0x40; // 

i = 500; // Delay

 do (i--);

 while (i ! = 0);
}

//
P1DIR |= 0x01; 		// Set P1.0 to output direction
P2IE |= 0x01; 		// P2.0 interrupt enabled
P2IES |= 0x01;		 // P2.0 Hi/lo edge
P2IFG &= ~0x01;		 // P2.0 IFG cleared

_BIS_SR(LPM4_bits + GIE);		 // Enter LPM4 w/interrupt
}

// Port 2 interrupt service routine
#pragma vector=PORT2_VECTOR
__interrupt void Port_2(void)
{
P1OUT ^= 0x01; // P1.0 = toggle
P2IFG &= ~0x01; // P2.0 IFG clearedf
}

//