Using msp430g2553 series turn this code from polling to interrupts using c language

#include

#define BUTTON1 ((P2IN & 0x02)== 0x00)

#define BUTTON2 ((P2IN & 0x04)== 0x00)

#define BUTTON3 ((P2IN & 0x08)== 0x00)

#define BUTTON4 ((P2IN & 0x10)== 0x00)

#define B1 (P1IN & 0x10)

#define B2 (P1IN & 0x20)

#define B3 (P1IN & 0x40)

#define B4 (P1IN & 0x80)

#define YellowLedOn (P1OUT |= 0x01)

#define GreenLedOn (P1OUT |= 0x02)

#define RedLedOn (P1OUT |= 0x04)

#define AllLedsOff (P1OUT &= ~0x07)

/**

* main.c

*/

int main(void)

{

WDTCTL = WDTPW | WDTHOLD; // stop watchdog timer

int Control = 0;

int NewPassWord[4];

int YourPassWord[4];

int EnterNewPassword = 0;

int EnterYourPassword = 0;

P2SEL = 0x00;

P1DIR = 0x0F;

P2DIR = 0xE1;

P1REN = 0xF0;

P2REN = 0x1E;

P1OUT = 0xF0;

P2OUT = 0x1E;

while(1){

if (Control == 0){

if (BUTTON1){

EnterNewPassword = 1;

}

if (EnterNewPassword == 1){

AllLedsOff;

NewPassWord[0] = B1;

NewPassWord[1] = B2;

NewPassWord[2] = B3;

NewPassWord[3] = B4;

if (BUTTON2){

EnterNewPassword = 0;

YellowLedOn;

Control = 1;

}

}

}

if (Control == 1){

if (BUTTON3){

EnterYourPassword = 1;

}

if (EnterYourPassword == 1){

YourPassWord[0] = B1;

YourPassWord[1] = B2;

YourPassWord[2] = B3;

YourPassWord[3] = B4;

if (BUTTON4){

EnterNewPassword = 0;

if ((YourPassWord[0] == NewPassWord[0])&& (YourPassWord[1] == NewPassWord[1])

&& (YourPassWord[2] == NewPassWord[2])&& (YourPassWord[3] == NewPassWord[3])){

AllLedsOff;

GreenLedOn;

Control = 0;

}

else{

AllLedsOff;

RedLedOn;

}

}

}

}

}

}