hwo to set up interrupt in dsp 2812

Hi everyone!
I am new in using dsp 2812.

I want to make an T3PINT interrupt.

I just read "TMS320x281x DSP System Control and Interrupts Reference
Guide"(spru078e) and
"TMS320x281x DSP Event Manager (EV) Reference Guide"(spru065e),

On page 84 in spru065e,and on page 122 in spru078e,
what's mentioned in the priority field seems different.
Why?

I am traceing the C of the example "sw_prioritized_interrupts"
mentioned in the document "C281x C/C++ Header Files and Peripheral
Examples".

It seems that cpu branchs to ISR to setup priority.Is this the way it
does? Or Is my understanding wrong?
(FILE: DSP281x_SWPiroritizedPieVect.c)

If priority can be set in code,why priority are mentioned in these
document?

Dose someone know how to accomplish this task?

Thanks a lot for your answers
Bell
.