Category: TSR libraries
INT 2D - ALTERNATE MULTIPLEX INTERRUPT SPECIFICATION (AMIS) [v3.6]
AH = multiplex number
AL = function
00h installation check
01h get private entry point
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 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 #02568), 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.
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=04h
SeeAlso: INT 2D/AL=05h,INT 2D/AL=06h,INT 2F"NOTES"