Resolving MIPS invalid program counter value: 0x00000000 Error

Discover effective solutions to fix the MIPS error "invalid program counter value: 0x00000000" when running code in the MARS simulator.
---
This video is based on the question https://stackoverflow.com/q/74691179/ asked by the user 'Lykoto' ( https://stackoverflow.com/u/20588909/ ) and on the answer https://stackoverflow.com/a/74691443/ provided by the user 'Erik Eidt' ( https://stackoverflow.com/u/471129/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: MIPS getting an error when running my code

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Resolving MIPS invalid program counter value: 0x00000000 Error: A Guide for Beginners

Encountering an error while running your MIPS code can be frustrating, especially as a newcomer to assembly language and the MARS simulator. One common issue that many beginners face is the invalid program counter value: 0x00000000 error. This guide will walk you through understanding why this error occurs and how to resolve it effectively.

Understanding the Problem

The MIPS assembly code you’ve written is intended to calculate the memory address of a pixel based on user-input coordinates. However, when you run the code, you receive the error stating an invalid program counter value. This happens because the MARS simulator defaults to running your program starting from the .text section, where your function is located before the main procedure. As a result, the program counter jumps to the start of the function without a proper call, leading to a failure.

Solutions Overview

To resolve this issue, you have three viable options:

Add a Jump to Main:

By placing a j main instruction directly after the .text section, you redirect the execution flow to the main function correctly.

Initialize Program Counter:

Adjusting the MARS settings can help. You can choose the option to “Initialize Program Counter to global main if defined.” This option allows the program to begin execution from the prescribed main function.

Reorder Your Code:

Another straightforward solution is to change the order of your functions. You can place the main procedure immediately after the .text section and before any other functions such as translate_coordinates.

Detailed Breakdown of Each Solution

1. Adding a Jump to Main

Here's how you can modify your code:

[[See Video to Reveal this Text or Code Snippet]]

Placing this at the very top will ensure that the execution starts in main, thus avoiding the mishap of running an uncalled function.

2. Adjusting MARS Settings

To change your settings in MARS:

Open the MARS simulator.

Go to the Settings menu.

Select Initialize Program Counter to global main if defined. This will set the appropriate starting point for execution each time you run your program.

3. Reordering the Code

Instead of having the translate_coordinates function before main, move main above all other functions like so:

[[See Video to Reveal this Text or Code Snippet]]

This stacked order ensures that the MARS program counter finds the main function as the first element in the text segment.

Conclusion

By following the solutions outlined above, you should be able to resolve the invalid program counter value: 0x00000000 error in your MIPS code running on the MARS simulator. Each option offers a way to refine your approach, whether it is through the code structure or simulator settings. Experiment with these methods, and you will soon be writing MIPS programs with greater confidence and clarity!

Feel free to reach out for additional help as you continue your journey into assembly language programming!