INT 2F - TBSCANX - GET STATUS
        AX = CA01h
Return: AH = BCD version number (v2.2+)
           = CAh for versions before 2.2
        AL = state (00h = disabled, 01h = enabled)
        CX = number of signatures which will be searched
---v2.0---
        BX = EMS handle, 0000h if not using EMS
---v2.3+---
        BX = segment of swap area, 0000h if not swapped
        DX = EMS or XMS handle (XMS handle if BX=0000h), FFFFh if not using EMS