Generally any compiler gives a note about how to use interrupts

The most common keyword is interrupt. so search the compilers maual with "interrupt" you will find the answer.

In KEIL/SDCC the following is the syntax.

voif timer0_isr(void) interrupt 1
{
}

interrupt is keyword with which compiler replaces RTI in place of RET.

1 is vector number. for timer 0 it is 1

if you want to specify register bank
voif isr_func(void) interrupt 3 using 1
{
}

using is keyword, 1 is the register bank that isr uses.