xcall GETPPN, ppn
GETPPN returns the current PPN in the two-byte format (first byte is project number, second byte is programmer number).
Note that the two-byte PPN format is largely obsolete, as of build 897, which supports decimal PPNs up to 999,999. You are better off using one of the other routines which retrieve the ppn, which retrieve the PPN in string format, such as LOG or GETJTB, or as a pair of two-byte binaries, such as XPPN.