The $NAM macro allocates storage for a NAM block and initializes
    certain NAM fields with default values and user-specified values.
    No value is returned for this assembly-time operation.

    Format

      $NAM  ESA=expanded-string-address,

            ESS=expanded-string-size,

            NOP=<NOCONCEAL PWD NO_SHORT_UPCASE SRCHXABS SYNCHK>,

            RLF=related-file-nam-block-address,

            RSA=resultant-string-address,

            RSS=resultant-string-size