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ALIENS.DOC
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Text File
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1979-12-31
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2KB
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67 lines
DOCUMENTATION FILE FOR ALIENS VERSION 1.1
ALIENS11.COM is a patchable version of the original ALIENS game
written in BDS C which can be used on most systems with a 24 X 80
terminal. This version does its console I/O thru calls to BIOS
instead of thru direct port I/O and therefore can be used with
most ported and memory mapped consoles. There are four strings
and two other locations that must be patched for a particular
configuration. Up to ten bytes are reserved for each string.
CURSOR POSITIONING STRING
This string starts at location 381DH, must be null terminated,
and allows for up to ten bytes including the null. At the
position in this string that the row position is to be located,
put an FF hex. At the position in the string that the column is
to be located, put an FE hex. This allows for the row and column
to be located anywhere in the cursor positioning string and in
any order.
EXAMPLE: (For a Heath/Zenith Z-19)
1B ;Escape character
59 ;'y'
FF ;Position for row
FE ;Position for column
00 ;string terminator
For many terminals the row and column values require a bias to be
added to them in the cursor positioning string. These values are
located at 3845H and 3846H respectively.
EXAMPLE:
Location Value
3845H 20 ;Add 32 to row value
3846H 20 ;Add 32 to column value
CURSOR ON, CURSOR OFF AND CLEAR SCREEN STRINGS
If your terminal allows turning the cursor on and off and allows
the clear screen function, these strings should be patched as
with the cursor addressing string. Don't forget to terminate the
string with a null(zero). If your terminal does not support one
or more of these functions, these strings should be set to nulls.
Starting Location String
3827H CURSOR ON
3831H CURSOR OFF
383BH CLEAR SCREEN
Use DDT to load the ALIENS11.COM and patch the new strings.
A>DDT ALIENS.COM
Use the S command to change the required locations.
-^C
A>SAVE 56 ALIENS.COM
This should complete the customization of ALIENS. Enjoy.
Don Wilkes, K4ZYP