Int 2D  - Alternate Multiplex Interrupt Specification (amis) [v3.6]        [t]

   AH = multiplex number
   AL = function
       00h installation check
       01h get private entry point
       02h uninstall
       03h request popup
       04h determine chained interrupts
       05h get hotkey list
       06h get device-driver information
       07h-0Fh reserved for future enhancements

       Return: AL = 00h (not implemented)
       other  application-dependent
   other registers vary by function (also see individual entries below)

Return: varies by function

Notes: programs should not use fixed multiplex numbers; rather, a program
     should scan all multiplex numbers from 00h to FFh, remembering the
     first unused multiplex in case the program is not yet installed.
     For multiplex numbers which are in use, the program should compare
     the first 16 bytes of the signature string to determine whether it
     is already installed on that multiplex number.  If not previously
     installed, it should use the first free multiplex number.
   functions other than 00h are not valid unless a program is installed
     on the selected multiplex number
   to be considered fully compliant with version 3.6 of the specification,
     programs must implement at least functions 00h, 02h (no resident
     uninstall code required), and 04h (return value 04h).  TSRs that
     provide hotkeys with which the user can activate them must also
     implement function 05h.  TSRs which provide DOS device drivers must
     also implement function 06h.  The absolute minimum fully-compliant
     implementation has an overhead of 64 bytes (80 bytes with function
     05h) plus 22 bytes per hooked interrupt (for the interrupt sharing
     protocol header and hook list entry).
   the signature string and description may be used by memory mappers
     to display the installed programs
   to be considered fully compliant, users of this specification must
     adhere to the IBM interrupt sharing protocol (see #2256), which will
     permit removal of TSRs in arbitrary order and interrupt handler
     reordering.  All TSRs following this specification should be
     removable unless they are loaded from CONFIG.SYS, though they need
     not keep the code for removing themselves resident; it is acceptable
     for a separate program to perform the interrupt unhooking and
     memory-freeing steps of removal.
   A sample public-domain implementation including example TSRs and
     utility programs may be found in a separate package distributed as
     AMISLnnn.ZIP (AMISL092.ZIP as of this writing).
   Please let me know if you choose to follow this proposal.  The
     signature and a list of the private API calls you use would be
     appreciated, as well.

See Also: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h

See Also: INT 2D/AL=05h,INT 2D/AL=06h,INT 2F"NOTES"

Format of interrupt sharing protocol interrupt handler entry point:
Offset Size    Description (Table 2256)
 00h  2 BYTEs  short jump to actual start of interrupt handler, immediately
         following this data block (EBh 10h)
 02h   DWORD   address of next handler in chain
 06h   WORD    signature 424Bh
 08h   BYTE    EOI flag
       00h software interrupt or secondary hardware interrupt handler
       80h primary hardware interrupt handler (will issue EOI)
 09h  2 BYTEs  short jump to hardware reset routine
       must point at a valid FAR procedure (may be just RETF)
 0Bh  7 BYTEs  reserved (0) by IBM for future expansion

Note:  when chaining to the prior handler, the interrupt handler must perform
     an indirect jump/call using the address at offset 02h in the
     ISP header.  This permits another AMIS TSR to hook itself into
     the chain at a position other than as the first handler to receive
     an interrupt.

See Also: INT F1/AH=01h"Common ISDN API",INT F1/AH=06h"CAPI",#3708