Format of MDEBUG data structure:
Offset	Size	Description	)
 00h	WORD	register SE
 02h	WORD	register OF
 04h	WORD	register FS
 06h	WORD	register FO
 08h	WORD	register AX
 0Ah	WORD	register BX
 0Ch	WORD	register CX
 0Eh	WORD	register DX
 10h	WORD	register SI
 12h	WORD	register DI
 14h	WORD	register DS
 16h	WORD	register ES
 18h	WORD	register BP
 1Ah	WORD	register SS
 1Ch	WORD	register SP
 1Eh	WORD	register FL (flags)
 20h	WORD	register R0
 22h	WORD	register R1
 24h	WORD	register R2
 26h	WORD	register R3
 28h	WORD	register R4
 2Ah	WORD	register R5
 2Ch	WORD	register R6
 2Eh	WORD	register R7
 30h	WORD	register R8
 32h	WORD	register CS, return-address
 34h	WORD	register IP, return-address
 36h	DWORD	saved pointer to data for key <F6> (v1.60)
		saved monitor address (v1.70)
 3Ah 12 WORDs	saved register values on last popup entry (for <F8> key)
		(original register values at popup entry of MDEBUG)
		AX, BX, CX, DX, SI, DI, DS, ES, BP, SS, SP, flags
 52h 12 WORDs	saved register values on last popup exit (for <SHIFT-F8> key)
		AX, BX, CX, DX, SI, DI, DS, ES, BP, SS, SP, flags
 6Ah	DWORD	address of the DOS-invars-table
 6Eh	DWORD	address of the InDOS flag
 72h	WORD	offset of the register which is used for the segment of the
		  first monitor window
 74h	WORD	offset of the register which is used for the offset of the
		  first monitor window
 76h	WORD	name of the register which is used for the segment of the
		  first monitor segment
 78h	WORD	name of the register which is used for the offset of the first
		  monitor window
 7Ah	WORD	pseudo register 1
 7Ch	WORD	pseudo register 2