Category: debuggers/debugging tools
Flags: callout or callback (usually hooked rather than called)

INT 2F - MDEBUG display driver - GET DRIVER STATUS

	AX = D000h
Return: CF set on error
	    all other registers must be unchanged)
	CF clear if successful
	    AL = FFh
	    AH = driver semaphor
		00h driver is not active
		01h driver is active
	    BX = CS of the driver
	    CX = driver version (CH = major, CL = minor, must be >= 013Ch)
	    DL = buffer semaphor
		00h driver is not pending
		01h driver is pending between functions 02h and 03h
	    DH = show semaphor
		00h driver is not pending
		01h driver is pending between functions 04h and 05h
Program: MDEBUG is a shareware memory-resident debugging tool by Bernd
	  Schemmer, including a memory monitor, an interpreter and a
	  disassembler
Range:	AH=C0h to AH=FFh, selected by switch or programmatically
Notes:	MDEBUG can use any two consecutive multiplex numbers between C0h and
	  FFh; the default is D0h for the display driver and D1h for the
	  command driver (call INT 60/AH=00h"MDEBUG" for the actual multiplex
	  numbers used)
	this function MUST be reentrant, as MDEBUG calls it after every popup
	  before any other actions.  The handler should not change any
	  registers if the display is in an unsupported mode or in a mode
	  MDEBUG supports itself, e.g. a normal text mode with at least 80x25
	  characters (i.e. 80x43 or 132x44 (v1.60+)). In this case MDEBUG will
	  not call any of the other functions for this popup session.
	MDEBUG will not call the other functions if the returned version is
	  less than the actual version of MDEBUG.
	if the driver is reentrant, DL and DH should be 00h
SeeAlso: AX=D001h,AX=D002h,AX=D003h,AX=D004h,AX=D005h