C program to use timer overflow interrrupt and real time interrupt

/* Increment Port A using TOF interrupt, and 
 * Decrement Port B using RTI interrupt */

#include "hc12.h"

main()
{
    DDRA = 0xff;        /* Make Port A output */
	PORTA = 0x00;       /* Clear Port A */
    TSCR = 0x80;        /* Turn on timer */
    TMSK2 = 0x84;       /* Enable TOF interrupt, overflow  */
                        /*   every 131 ms */
    TFLG2 = 0x80;       /* Clear timer interrupt flag */

	DDRB = 0xff;        /* Make Port B output */
	PORTB = 0x00;       /* Clear Port B */
	RTICTL = 0x87;      /* Enable RTI interrupt; rate = 65 ms */
    RTIFLG = 0x80;      /* Clear RTI flag */

    enable();           /* Enable interrupts (clear I bit) */
    while (1)
    {
        _asm("wai") ;   /* Do nothing - go into low power mode */
    }
}

@interrupt void toi_isr(void)
{
    PORTA = PORTA + 1;  /* Increment Port A */
    TFLG2 = 0x80;       /* Clear timer interrupt flag */
}

@interrupt void rti_isr(void)
{
    PORTB = PORTB - 1;  /* Decrement Port B */
    RTIFLG = 0x80;       /* Clear RTI flag */
}

vector.c file for setting interrupt vectors

/*      INTERRUPT VECTORS TABLE 68HC12
 */
void toi_isr();         /* Timer overflow ISR */
void toi_isr();         /* Real Time Interrupt ISR */

/* Vectors at 0xFFD0 on standard HC12; remapped to 0x0B10 with D-Bug 12 */
void (* const _vectab[])() = {
        0,              /* BDLC            */
        0,              /* ATD             */
        0,              /* reserved        */
        0,              /* SCI0            */
        0,              /* SPI             */
        0,              /* Pulse acc input */
        0,              /* Pulse acc overf */
        toi_isr,        /* Timer overf     */
        0,              /* Timer channel 7 */
        0,              /* Timer channel 6 */
        0,              /* Timer channel 5 */
        0,              /* Timer channel 4 */
        0,              /* Timer channel 3 */
        0,              /* Timer channel 2 */
        0,              /* Timer channel 1 */
        0,              /* Timer channel 0 */
        rti_isr,        /* Real time       */
        0,              /* IRQ             */
        0,              /* XIRQ            */
        0,              /* SWI             */
        0,              /* illegal         */
        0,              /* cop fail        */
        0,              /* cop clock fail  */
        (void *)0xff80, /* RESET           */
        };