Collection of Tools & Utilities/Collection of Tools and Utilities.iso/batchut/int11.zip/INT.DOC

Text File | 1992-03-24 | 15KB | 310 lines

               Documentation for INT.COM version 1.1

        INT.COM is Copyright (C) by David Abbott,  August 1990.

     This documentation,  with the exception of the disclaimer and
  licence agreement,  is also Copyright (C) by David Abbott 1990-1992
                          All Rights Reserved.


CONTENTS:

    * Warning
    * Disclaimer
    * Introduction
    * Usage
    * Examples
    * Beginner's guide
    * History
    * Bugs
    * Licence agreement


WARNING:

    This software has the ability to call DOS and BIOS routines
    which,   if used incorrectly,  may cause unintentional data
    loss. Be sure you understand exactly what a command will do
    before executing it. The potential to format your hard disk
    with one command is contained herin!


DISCLAIMER:

    The author makes no warranty, either implied or expressed,
    including, without limitation, any warranties with respect
    to the software documented here, its quality, performance,
    or fitness for any particular purpose.   In no event shall
    the author be liable for damage, whether direct, indirect,
    special, incidental, or consequential, that arise from the
    use of or any defect in the software.   The entire risk as
    to the quality and performance of the software is with the
    user.  By using this program, you acknowledge:
    (1) to have read and understood all parts of this
        disclaimer, the warning above,  and of the licence
        agreement appearing at the end of this document, and
    (2) to have agreed with and accepted all of their
        provisions.



INTRODUCTION:

    Have you ever wanted to check for a key press in a batch file, without
having the batch file wait for input?  If you have an EGA/VGA colour system,
wouldn't it be nice to be able to have full control over the colours a program
uses,  even if the program does not normally allow this?  Well now, thanks to
INT.COM,  virtually anyone can have this power!  INT.COM is a small but very
powerful utility,  which enables the easy execution of software interrupts
from the DOS command line.  Those users not experienced with software
interrupts or who don't know what a CPU register is may like to read now the
BEGINNER'S GUIDE to INT.COM which appears later in this document.  The rest of
you can continue on here.


USAGE:

              int R N [ah al bh bl ch cl dh dl si di] [;STRING]
        or:   int R N [ax bx cx dx si di] [;STRING]

    where R is one of A,a,B,b,C,c,D,or d indicating which general
    purpose register is to be returned as a DOS errorlevel: lower case
    indicating the lower byte, uppercase the high byte (e.g. D returns
    dh, d returns dl).

    N is the interrupt number to be called (in hexadecimal)

    The first group of optional arguments are 1,2,3, or 4 digit hex
    numbers specifying the contents of 8 or 16-bit registers in the
    order indicated. Thus the following command lines are equivalent:
        int a 12 34 56 07 89
        int a 12 3456 0789
        int a 12 34 56 789
    It is only necessary to supply values up to the last register you
    need to specify.  The remaining registers will be set to zero.
    NOTE: The segment registers cs,ds,es, and ss all point to the
    Program Segment Prefix (PSP).  This can be useful when supplying
    additional data on the command line (see below).

    ;STRING is used to supply additional data for some interrupts.  All
    characters appearing after the semi-colon are ignored by INT.COM,
    but are accessible to the interrupt called.  To use this feature,
    all one has to know is that the offset from the start of the PSP to
    the first character of the command tail is 81h.  Thus it is a simple
    matter to count up to the semi-colon and find the offset of the
    extra data. For example,  the following line uses int 21h, function
    9 to write the string "Hello World!" to the screen:
        int a 21 09 00 0000 0000 009c;Hello World!$
    (with the first space after int at offset 81h, Hello World must
    start at offset 9ch,  to which dx is set).

NOTE: INT.COM does very little checking of command line syntax.  As long as
the first argument is legal,  and no illegal characters appear before the
semi-colon,  INT.COM will be satisfied.  It is therefore most important that
you check the command line before execution,  or some nasty results may
follow!


EXAMPLES:

    The following examples illustrate the power and convenience of
    INT.COM,  especially when used in batch files.  To get the most
    out of INT.COM,  however,  you will need a reference listing the
    DOS and ROM BIOS interrupts.  There are many books available
    containing this information,  as well as some useful public domain
    and shareware databases.


* Check to see if ESC key has been pressed,  without waiting.  The first int
  command checks for the presence of a keypress,  the second reads it:
echo off
int a 21 0b
if not errorlevel 1 goto :nokey
int a 21 08
if not errorlevel 28 if errorlevel 27 goto :esc_pressed
rem: The above line tests errorlevel (to which register al was returned) for
rem: the value decimal 27 (ASCII code for ESC).
goto :key_not_esc


* single line batch file to set new video mode (I call this vmode.bat):
int a 10 00 %1
  This accepts the video mode number in hexadecimal.  Thus to set video mode
  on a CGA to 40x25 16 colour text, use "vmode 6".  For 640x200 16 colour
  graphics on a VGA/EGA, use "vmode E".  Consult your video card's
  documentation to see if there are other useful modes available.  For
  example, a Paradise compatible VGA card can be switched to 132 column text
  with "vmode 55".


* set VGA/EGA displayable colour 0Eh (yellow) to a different shade of yellow
  from the available palette:
int a 10 1000 37 e


* set VGA palette colour 0 (black) to very dark blue by specifying RGB values:
int a 10 1010  0000   0 11 0
             col.reg. G B  R  (remember they are in hexadecimal)
  To use this for other colours,  it is helpful to know which palette colour
  registers actually correspond to which displayable colours in the default
  palette selection.  They are as follows:
    displayable colour:  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    colour from palette: 00,01,02,03,04,05,14,07,38,39,3a,3b,3c,3d,3e,3f
  So to specify the RGB values for yellow, you would need to change register 3e.


* disable default colour palette/register loading on VGA mode set:
int a 10 12 01 0031
  to re-enable, use:
int a 10 12 00 0031
  This can be very useful after setting precisely the colours you want to use
  in a particular application,  to prevent these colours being reset by the
  application program itself if it resets the video mode.  In this way, you
  can use VGA colours in programs that don't support the VGA (but note that
  some programs which switch video modes during execution rely on default
  loading being enabled,  in which case you could be left with weird colours
  if you use this trick)!



BEGINNER'S GUIDE:

        Hidden inside every PC are many small programs which perform tasks
such as reading the keyboard,  setting different colours, changing video
modes,  or writing text to the screen.  These programs are contained in two
places:  the ROM BIOS (Read Only Memory Basic Input Output System) and DOS
(Disk Operating System).  Normally,  one has to write programs in assembly
language or a higher level language to access these operating system routines.
That's because they're called by what are known as software interrupts.  When
a particular interrupt is called, the computer executes the corresponding BIOS
or DOS routine,  and then passes control back to the calling program.  What's
needed, therefore, is a small program which will call the interrupt for us,
and this is exactly what INT.COM does.

        INT.COM is a small program which allows software interrupts to be
called directly from the command line,  or from within batch files. Those of
you familiar with the available DO