HPSWTONMPLABEL
CM callable only.
Allows CM user programs, user libraries, and system code to invoke NM
procedures as follows:
* Convert CM references in the argument list to virtual NM
addresses.
* Change the execution mode.
* Invoke the NM procedure specified by the CM caller.
U32V I16V I16 I16 I16V
HPSWTONMPLABEL(proc,nparms,arglist,argdesc,functype);