How jump after interrupt to another function (other then I left)?

Hello,

Im working with f28335 without BIOS.
and writing in C.

I'm intend to use with Timer_1 as interrupt.
the idea is that in case interrupt
the ISR  will decide how the program will
continue after the interrupt.

just to be clear, in case that the code
running function "func_A". and now interrupt
event occur
I need to change the code flow to
function B "func_B". I'm not suppose to
return from interupt to "func_A" but to
continue directly (at the end of ISR)
to "func_B".

I read about the cpu interrupt .
and i see that when interrupt occur:
1. the pc is saved in the stack.
2. at the interrupt end (with the instruction IRET)
    the PC restore automatically from the stack.

hence, in order to jump after the interrupt to
another funcion, the ISR need to change
the PC address that store in the stack.

1. How i do it?
2. where exactly the place of the PC
   that  store in the stack?
3. where can i get asm code examples?

Thanks.
Asher.