INT 1A - SNAP.EXE 3.2+ - "SNAP_GETANCHOR"
        AX = 7101h
        STACK:  WORD    anchor number (0000h-0009h)
Return: AX = anchor's value
        STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
          which implements the Simple Network Application Protocol