Interrup Register Bank

Dear All,

I'm using this interrupt on my program

void timer1_ISR (void) interrupt 3 //timer1 interrupt services routine
{
..
}

void it_ext1(void) interrupt 2	// external interrupt INT1
{
..
}

void timerisr(void) interrupt 1   //timer0 interrupt services routine
{
..
}

static void com_isr (void) interrupt 4  //SERIAL COMMUNICATION INTERRUPT SERVICES ROUTINE
{
..
}


void i2c(void) interrupt 5    //i2c interrupt services routines
{
..
}

and I didn't specified which register bank to use on every interrupt routines.

does it can crash my program?

I've seen few example which specified the register bank.

Can anyone explain more on the uses of register bank during interrupt service routine


Thanks
Juru Dala

PS: I'm using 668 chip