INT 2fH ae00H: Notify Pending Command

                                                 Compatibility: ◄Undoc► 3.0+ 
 Expects: AX    ae00H
          DX    ffffH
          DS:BX address of length-prefixed command-line buffer
          DS:SI address of an 8-byte upshifted, blank-padded command name
          ──────────────────────────────────────────────────────────────────
 Returns: AL    flag: 00H = no, ISR does not want to intercept
                      ffH = yes, ISR will process the command
          ──────────────────────────────────────────────────────────────────
    Info: This is intended as a way to intercept commands typed at the DOS
          command prompt before COMMAND.COM gets a chance to process them.

          A TSR program hooks INT 2fH and watches for AX=ae00H.  Then it
          compares the text at DS:SI with a command that it wishes to
          intercept.  If it wants to handle that command, it sets AL=ffH
          and executes an IRET.  If it has no interest, it just passes
          control to the next INT 2fH handler.

          Don't process the command yet.  When you signal interest in a
          command, COMMAND.COM will immediately execute INT 2fH ae01H and
          you should take action only upon that event.

    DS:BX On entry, DS:BX points to a command line buffer in the form:
          RawCmdLineRec
           Offset Size Contents
           ▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
            +0      1  bBufLen   length of the buffer
            +1      1  bTextLen  length of the command-line text (abText)
            +2      n  abText    text of the command line
            2+n     1  bCr       one byte of 0dH (Carriage Return)
                  3+n            size of a RawCmdLineRec structure

          Note that this is layout is similar to that used in DOS fn 0aH
          (get buffered string input), which COMMAND.COM uses to obtain
          user input.

          When intercepting commands, you must save a copy of this buffer.
          See Notes, below.

    DS:SI On entry, DS:SI points to an upshifted, blank-padded version of
          the first word on the command line.  This text will be exactly
          eight characters long; space characters (ASCII 20H) are appended
          to the text to fill-out the 8-character buffer:
          CmdNameRec
           Offset Size Contents
           ▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
            +0      8  abCmd     blank-padded command name
                    8            size of a CmdNameRec structure

       AL If you wish to intercept this command, set AL to ffH and return
          to DOS via an IRET.  COMMAND.COM will issue an INT 2fH with
          AX=ae01H immediately, and you can take action then.

          If you do not wish to intercept this command, you should pass it
          down the chain by using a FAR JMP to the address which originally
          handled INT 2fH when your TSR was installed.

   Notes: When COMMAND.COM issues the subsequent INT 2fH ae01H, it does not
          supply the DS:BX pointer to the full command line; therefore, you
          must save this address for use in the ae01H subfunction.


See Also: INT 2fH aexxH Command Processor Hook
          INT 2fH: Multiplex Interrupt
          DOS Functions
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