Interrupt with input P8.7

I dont anderstand how to make an external interrupt with the input P8.7 with a pulse.
I need to have an Interrupt from a pulse at the front egde.
I have write this part of code, but this code dont work.

In the main subroutine i have write this:
CCM5 = 0x1000;
CC23IC = 0x0064
CC23IE = 1;
IEN = 1

and write the subroutine interrupt code:

void myint (void) interrupt CC23INT = 55
{
.....
}

What i must write more at the main subroutine to this external interrupt work well?
Thanks very much to answer me.