Programmer Power Tools/Programmer Power Tools.iso/turbopas/tp_tsr.arc/README

Text File | 1989-02-11 | 8.1 KB | 154 lines

 ═════════ Turbo 5.0/4.0 stay-resident demonstration package ══════════

   TP-TSR                 2/11/89                Richard W. Prescott

   This package illustrates a method for writing TP4/5 interrupt
   routines with sufficient power and flexibility to support
   sophisticated resident applications.  The interrupt hook and
   return procedures are written in assembly language, however the
   remainder of the application can be written entirely in Pascal,
   can use up to 64K stack, and can Chain or Return from Interrupt
   from any point in the Pascal Code.  All source code is provided,
   and all assembly source code is contained in the Units CONSOLE and
   DOS21_0A which are provided in both source and compiled form.
   Users without an assembler can redesign everything but the
   interrupt hook and return procedures.


   Files provided in this package:

   README         (This file)
   DOS21_0A.PAS   Interrupt Unit (Pas/Asm Source)
   DOS21_0A.TPU   Interrupt Unit (Compiled w Turbo Version 5.0)
   DOS21_0A.TP4   Interrupt Unit (Compiled w Turbo Version 4.0)
   CONSOLE.PAS    CRT-type Procedures & Functions (Pas/Asm Source)
   CONSOLE.TPU    CRT-type Procedures & Functions (Compiled w Turbo 5)
   CONSOLE.TPU    CRT-type Procedures & Functions (Compiled w Turbo 4)
   CPATH.PAS      Simple resident program (Pascal Source)
   CPATH.EXE      Simple resident program (Compiled)
   CMDQ.PAS       Command editor program (Pascal Source)
   CMDQ.EXE       Command editor program (Compiled)


   The sample interrupt Unit provided installs an interrupt handler
   for the DOS function 0Ah (Buffered Input), which is the function
   used by COMMAND.COM and DEBUG.COM to request keyboard input.
   Routines are provided to return (IRET) to the calling program or
   to Chain to the next program in the interrupt chain.  These
   routines can be invoked from any point in the service routine.
   Simple and obvious modifications can be made to the interrupt unit
   to create handlers for other functions and/or interrupts.

   The programs CPATH and CMDQ provide concrete examples of resident
   programs using the DOS21_0A Interrupt Unit.  CPATH is the shortest
   program I could think of which nonetheless uses the interrupt unit
   to do something at least slightly useful.  It checks the current
   disk drive, and if it is 'C' or greater, writes the current
   directory path (e.g.  C:\TURBO> ) before chaining to the original
   interrupt routine to service the input request.  The advantage
   over the $p $g method described on p595 of the Turbo 4.0 Owner's
   Handbook and on p317 of the Turbo 5.0 User's Guide is that CPATH
   does not cause the noticable pause between each DOS command when
   the active drive is a floppy disk drive.  It assumes that most
   users do not use subdirectories on their floppy disks.

   CMDQ is a more ambitious undertaking which provides all the
   features of a basic command line editor with command recall.  It
   is written in a modular fashion and is heavily commented so that
   you may easily customize it to your liking.  The basic edit key
   configuration is compatible with CED by Chris Dunford and NDOSEDIT
   by Jack Gersbach:  use the Up Arrow to move back through previous
   commands, and Down Arrow to move forward again.  While any command
   is displayed, use Home, End, Left, Right, Ctrl Left, and Ctrl
   Right to move around, and Esc, Ctrl Home, Ctrl End, Backspace, and
   Delete to delete all or part of a line.  Insert toggles between
   insert and overwrite mode, and Enter, from any position on the
   line, executes the command.  Refer to the comments in CMDQ.PAS for
   a further description of what each key does.

   Note that neither CPATH nor CMDQ could be written using the built-
   in "Interrupt Procedure" provided in Turbo version 4/5, since it
   does not provide for chaining to the previous interrupt vector.

   For those interested in designing interrupt units for other
   applications, two features of the present unit are worth noting.
   First, since it is impossible for DOS to be active at the time of
   the interrupt which results in a call to our Pascal code, we can
   make full use of DOS functions (including WRITELN, FindFirst, etc)
   within the Pascal code of the service routine.  Handlers for
   interrupts other than $21 must either insure that DOS is not
   active when they "wake up", or avoid using DOS function calls
   within the handler.  Second, since these programs are active at
   EVERY function 0A request, there is no need for a separate
   Interrupt $16 or $09 routine to check for a "Hot Key".  Programs
   which do install more than one interrupt handler must provide a
   separate stack area for each handler, or use the caller's stack.

   The Units CONSOLE and DOS21_0A were compiled and assembled using
   Turbo Pascal Version 5.0 and TP&Asm Version 2 ß.  TP&Asm provides
   an integrated compile-time assembler within the Turbo development
   environment (and the command line compiler TPC).  The result is an
   ASSEMBLY Development Environment which is identical to your PASCAL
   Development Environment, and which allows you to mix assembly
   language sections freely within your Pascal code and to make
   simplified assembly references to all Pascal variables.  It
   provides fast assembly with no additional disk access, and reports
   assembly syntax errors on the standard Turbo error line with
   cursor placed on the error.  It accepts the standard syntax of
   both MASM and A86, but also provides certain enhancements such as
   the placement of named data in the Code Segment which is used in
   the interrupt unit DOS21_0A.

   TP&Asm Version 2.0 will be available from me for $49 plus $3 P&H.
   The current Beta Test Version 2 ß is available now for $39 plus $3
   P&H, with a free upgrade to 2.0 when it becomes available.

   A sharable Memory Mode version called TP&Asm-M is also available.
   TP&Asm-M provides the same assembly language capabilities as TPA,
   but is intended only for assembly language development within the
   Turbo 4.0 or 5.0 integrated environments, and therefore does not
   have the capability of compiling to disk.  (You can of course read
   and save Pascal and Assembly SOURCE files with both programs).

   The TP&Asm-M distribution disk can be ordered from me for $5 plus
   $3 P&H, with the $5 being credited toward subsequent registration
   of TP&Asm or TP&Asm-M.  It can also be downloaded from the IBMPRO
   or BPROGA forums on CompUServe.  Look for TPA2-A.ARC and TPA2-R.ARC.


   To order TP&Asm, please send a check or money order payable to:

                         Richard W. Prescott
                         724 Sauk Ridge Trail
                         Madison, WI  53705

   Please include the following information:

   1. Full Version number of the Turbo Pascal compiler you now use.

   2. Your registration number for that compiler.

   3. If you obtained TP&Asm-M from a bulletin board:
      3a. Area code and phone number of that bulletin board
      3b. Full Version number of the TP&Asm-M version you have
      3c. Directory Date of the README file


   The source and compiled code in this package is copyrighted as
   indicated.  You may share this package and/or upload it to
   bulletin boards as long as no fee is charged.  You may of course
   make modifications to these programs for your own use, and you may
   distribute these modifications with the package.  The original
   unmodified files must all be present.

   Registered owners of TP&Asm may distribute programs using any of
   the source code or compiled units in this package in original or
   modified form.  Please give appropriate credit.

   If you distribute programs written using TP&Asm, please help me
   spread the word by including a statement like the following:

          This program was compiled and assembled using
         Turbo Pascal Version xxx and TP&Asm Version yyy.