Adding one more ADC channel to read inaddition to current channel

#include <msp430.h>
#define Smclk 1048576u /* default frequency */
#define Size 500 /* size of result buffer */

__no_init volatile unsigned results[Size];
volatile int oldest = 0;
volatile int filled = 0;

int _system_pre_init(void)
{
   WDTCTL = WDTPW | WDTHOLD;
   return(1);
}

void main( void )
{

// Initialize ADC12_A to sample internal-temperature-sensor
  REFCTL0 = REFMSTR + REFON;
  ADC12CTL0 = ADC12SHT0_4 + ADC12REFON + ADC12ON;
  ADC12CTL1 = ADC12SHS_1 + ADC12SHP + ADC12CONSEQ_2;
  ADC12CTL2 = ADC12PDIV + ADC12RES_2;
  ADC12MCTL0 = ADC12SREF_1 + ADC12INCH_10;
  P2SEL = BIT2;
  ADC12IE = ADC12IE0;
  ADC12CTL0 |= ADC12ENC;

// Set up TA0CC1 to generate a 500 Hz square wave to start ADC12 conversion
  TA0CCR0 = Smclk/(500) - 1;
  TA0CCR1 = TA0CCR0 - 20;
  TA0CCTL1 = OUTMOD_3;
  TA0CTL = TASSEL_2 + MC_1;

  while (1)
  {
    __bis_SR_register(CPUOFF + GIE);

// Do data processing here
// The oldest result is in results[oldest]
//   ...   ...  ...  ...
//   ...   ...  ...  ...
//   ...   ...  ...  ...
// This must be accomplished well within 2 msec.
// You may need to increase the core voltage and speed up MCLK

  }
}

#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR(void)
{
 if (oldest == 499)
           {
          oldest= 0;
           }
          else
          {
              oldest=oldest+1;
          }
      results[oldest]=ADC12MEM0;
    __bic_SR_register_on_exit(CPUOFF);
}