Xinu - Setting new priority for a Suspended state process

Question

I have created a process X in Xinu along with other two processes (y, z). The y and z are high priority than X, so they both are running as per scheduling policy.

In the backend, I want to increment the priority of X by one, based on a condition. But whenever I try updating the process's "prprio" in the proctab, I am encountering:

New Priority for TRAP

Xinu Trap

Is there way, that I can update the process priority to a desired number, once the process is created?

Answer 1

I just found the answer for this, there is a predefined function chprio is available to update, which I missed earlier. But not sure why I got TRAP when I put similar kind of code!