These are the tracing commands I typed in one day to see what was
in R5 & R9 at a certain point in CP under XA.
 
TRSOURCE ID RICK TYPE DATA LOC 34C174 4560C23A DL G5 G9
             |                   |       |
             |                   |       |----  The instruction in hex.
             |                   |----  CP's virtual address.
             |----  Any name.
 
TRSAVE ID RICK DASD TO * SIZE 2000
TRSOURCE ENABLE ID RICK
...  Then I caused the trap to be hit.
TRSOURCE DISABLE ID RICK
Q SDF    Tells you what system data files there are.  You want the TRF files.
Q TRF    You can see which one is yours by the filename = RICK.
TRACERED nnnn   This takes that TRF file and converts it to a spool file.
                TRACERED is documented in the DVF book.
PEEK            TRACER