improved readme

[Myrausman]

Improved README:

The following changes were made to the riscv-opcodes README file to enhance the overall readability and clarity, making it more approachable for both new and experienced contributors:

1. Enhanced Section Organization:

   • Clear Table of Contents added at the beginning for easy navigation, including key sections such as Project Structure, File Naming Policy, Encoding Syntax, and Usage.

2. Improved Project Structure Clarity:

   • The project structure is now visually represented using a directory tree. This simplifies understanding the role of each file in the repository.

3. File Naming Policy Explanation:

   • The section on file naming conventions for instruction encodings is reorganized for improved clarity. The file naming rules now explicitly explain the format for rv_x, rv32_x, rv64_x, rv_x_y, and unratified/.

4. Detailed Encoding Syntax:

   • The Encoding Syntax section was expanded to include more specific examples and structured explanations of regular instructions, pseudo instructions, and imported instructions. This makes it easier for contributors to grasp the instruction format and syntax.
   • Bit encoding types and operators are also described in detail, with examples, for a better understanding of how the encoding works.

5. Clear Workflow for parse.py:

   • A new section outlining the flow of the parse.py script was added, including a breakdown of the different phases (regular instructions, pseudo instructions, imported instructions) and the checks performed in each phase. This improves understanding of how the script processes instructions and generates artifacts.

6. Artifact Generation Process:

   • Added clearer, step-by-step instructions on how to generate specific artifacts (like C, Chisel, LaTeX, etc.) using the parse.py script and the Makefile. This helps users understand the full scope of available artifacts and how to produce them.
   • The prerequisites for generating these artifacts are now specified, along with explicit command examples to ensure users can run the script with ease.

7. Simplified Debugging Instructions:

   • Instructions for enabling debug logging in parse.py have been made more prominent, helping users troubleshoot issues more effectively.

8. Contribution Guidelines:

   • The section on contributing to the repository has been expanded with clear steps for creating a pull request (PR) and ensuring that all tests pass before submitting changes.

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[rpsene]

@Myrausman can we add a short text explaining how to set those options?

[rpsene]

@Myrausman take a look a the 2 initial comments.

git apply ../op.patch
../op.patch:381: trailing whitespace.

1. Create the Extension File:
   warning: 1 line adds whitespace errors.

[Myrausman]

Hi @rpsene, I've added an example for setting options and I'm using trunk for formatting—please let me know if the changes look good or if you'd prefer a different format.