Int 7F Fn ABCD  - IBM 8516 Touch Screen Device Driver - Get API Entry      [V]

   AX = ABCDh
   BX = 0000h

Return: AX = total number of functions available
   ES:BX -> entry point array

See Also: AX=0104h,AX=0105h

Function numbers:
 00h   check initialization and reset
 14h   set user-defined subroutine

Notes: each driver function takes two stack parameters using Pascal calling
     conventions: address of parameter block and address of results buffer
   all pointers are FAR pointers
   on return, AX contains the status of the call:
       AX = 0000h successful
        0001h invalid input
        0002h interface error
        0003h unable to perform function

Format of parameter block for function 00h:
Offset Size    Description
 00h   WORD    0000h (function number)

Note:  this function should be called before any other device driver functions

Format of results buffer for function 00h:
Offset Size    Description
 00h   WORD    touch screen status
       0000h unavailable
       0001h uncalibrated
       FFFFh available
 02h   WORD    aux mouse status (0000h not present, FFFFh present)

Notes: the following driver parameters will have been reset to zero:
     touchdown counter, liftoff counter, position at last touch, position
     at last lift, int call mask, select on count, select off count,
     pos select on count, pos select off count.
   the following driver parameters will have been reset as listed:
     mouse emulation mode: left on
     thresholds: 46 on screen, 96 push harder, 80 push release
     x, y hysteresis: 400
     data repeat rate: 40/sec
     select mechanism: push-harder - first-touch
     coordinate origin: upper left corner
     filter frequency: medium
     data block mask: all enabled
     click lock: on