update README.md

README.md

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 # turbopascal X-LIB UNiT V0.3á*
 This Pascal unit, xlibunit, is a graphics library designed for use in Turbo Pascal programs. It provides various procedures for initializing and manipulating VGA graphics modes, handling color palettes, and drawing on the screen. It's particularly useful for creating graphic demos.
 
+## System Requirements
+- Turbo Pascal 6.0
+- MS-DOS or compatible environment
+- VGA graphics card
+
+## File Structure
+
+| File | Description |
+|------|-------------|
+| `xlibunit.pas` | Pascal unit source code |
+| `xlibunit.tpu` | Compiled Turbo Pascal Unit |
+| `COMPILE.BAT` | Batch script to compile the unit with Turbo Pascal |
+| `intel.txt` | Reference documentation for Intel 8086 instruction set |
+| `LICENSE` | MIT License |
+
+## Usage
+Include the unit in your Turbo Pascal program and call the methods:
+```pascal
+program MyGraphicsDemo;
+uses xlibunit;
+begin
+  initxlib;    { Initialize VGA mode 13 }
+  { ... your graphics code ... }
+  exitxlib;    { Return to text mode 3 }
+end.
+```
+
+## Types and Variables
+
+| Type / Variable | Description |
+|-----------------|-------------|
+| `paltype` | Array of 768 bytes (256 RGB triplets) used for palette data |
+| `textpal` | Array of 3x16 bytes storing text mode palette on unit initialization |
+
 ## Compile
 Compile.bat uses Turbo Pascal 6.0 installed in c:\progrs\tp\
 ```
@@ -45,6 +79,14 @@ compile.bat
 | `locate`           | Sets the cursor position.                                                       |
 | `key`              | Checks if a key is pressed.                                                       |
 
+## Author
+
+Created by Stefan Koelle. FidoNet: 2:2480/330
+
+## Contributing
+
+Contributions are welcome. Please credit the author in your program and consider sending a FidoNet message to Stefan Koelle (2:2480/330) if you use this library.
+
 ## Lizenz
 
 Lizenziert unter der [MIT License](LICENSE) - Copyright (c) 2026 Stefan Koelle (https://stefankoelle.de)