Folks when writing PIC assembly:

Do NOT mix variables declared UDATA_OVR that
are used in interrupt and non-interrupt level code!
That bug took some time to figure out!
I was trying to be too clever this time......

Now I use overlayed variables ONLY in non-real
time (non-interrupt code.)  The file registers (variables)
used in interrupt service routines are either just UDATA
or UDATA_SHR.

I have yet figure out if UDATA will go down into or over
UDATA_SHR space if you run out of UDATA space.  Guess
we'll see.

GL, Walt...