Problem Interfacing keypad with msp430f5529 lp

Hi all,

I am working on a project where i have to interface a matrix keypad with 40 keys(5x8). I tried implementing the code with 4 push buttons, kind of like a 2x2 matrix and using 4 leds as output. This is the code I wrote

#include <msp430f5529.h>

/*
 * main.c
 */

volatile int col = 0;
volatile int row = 0;

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

     P6SEL &= 0x00;   //P6 initialization
     P6OUT = 0x00;
     P6DIR = 0x1F;
     P6OUT = 0x00;

     P3SEL &= 0x00;   //P3 initialization
     P3OUT = 0x00;
     P3DIR |= 0x03;
     P3OUT &= 0x00;

     P1SEL &= 0x00;   //p1 initialization
     P1OUT = 0x00; // initializing all outputs to low
     P1DIR &= 0x00; // P1 as input
     P1REN |= 0x60; // P1.5,6 Enable Pullup/Pulldown
     P1OUT |= 0x60; // P1.5,6 pullup
     P1IES |= 0x60; // P1.5,6 Hi/lo falling edge
     P1IFG &= 0x00; // P1.5,6 IFG cleared just in case
     P1IE |= 0x60; // P1.5,6 interrupt enabled

     __bis_SR_register(GIE);
     while(1)
      {
    	 if (col == 0);
    	 else
    	 {
    		 row = 1;
    		 P3OUT |= 0x01;
    		 if (row == 1)
    		 {
    	      row = 2;
    	      P3OUT |= 0x02;
    		 }
    	 }
      }
	
	return 0;
}

#pragma vector = PORT1_VECTOR
 __interrupt void Port1 (void)
 {
 switch(__even_in_range(P1IV,16))
   {
   case 0:break;
   case 2:break;
   case 4:break;
   case 6:break;
   case 8:break;
   case 10:break;
   case 12:
   {
	   if (row == 0)
	   {
	   col = 1;
	   P1IES &= ~BIT5; //P1.5 IFG cleared
	   P1IFG &= ~BIT5; // rising edge
	   }
	   else
	   {
	   P3OUT &= 0x00;
	   int i;
	   for(i=0; i<=200; i++)
	   __delay_cycles(1000);
	   P1IFG &= ~BIT5; // P1.5 IFG cleared
	   P1IES |= BIT5;  //Falling Edge
	   if (row == 1)
		   P6OUT ^= BIT0;
	   if (row == 2)
		   P6OUT ^= BIT1;
	   col = 0;
	   row = 0;
	   }
   }
	   break;
   case 14:
   {
	   if (row == 0)
	   {
	   col = 2;
	   P1IFG &= ~BIT6;  // P1.6 IFG cleared 
	   P1IES &= ~BIT6;  // rising edge 
	   }
	   else
	   {
	   P3OUT &= 0x00;
	   int j;
	   for(j=0; j<=200; j++)
	   __delay_cycles(1000);
	   P1IFG &= ~BIT6; // P1.6 IFG cleared
	   P1IES |= BIT6; // falling edge
	   if (row == 1)
		   P6OUT ^= BIT4;
	   if (row == 2)
		   P6OUT ^= BIT3;
	   col = 0;
	   row = 0;
	   }
   }
	   break;
   case 16:break;
   default: break;
   }

 }

Sometimes key presses are not registered properly. Pressing a particular key produces output for a different key. Is there a problem in my logic or the way i implemented it ?

any help is greatly appreciated.

Regards,

~Ram