valtrix.opensource

This is a space for providing Open source tutorials for RISCV enthusiasts. This tutorial introduces you to the concept of RISCV programming with just a few tutorial sections which contains simple and easy to understand pieces of code with all steps and procedures to replicate the same on your system.

Setting up

This tutorial assumes that you have spike or any RISCV simulator up and running on your system. Clone this repositiory on your system and just follow the instructions provided inside.

Usage

• Following the tutorial step by step starting with the first one is recommended for beginners. You are also requested to go through the RISCV assembly explanation given here.
• For people with a bit of RISCV programming experience could just look into parts of the tutorial of interest to them.

General RISCV Assembly Explanation

• The RISCV assembly file(.s format) is subdivided into different sections.
• Some sections are exclusively for providing comments(.text section) and some are for storing only data(.data section).
• There are a few other section labels which you could come across and are listed down below with their corresponding explanations :-
  • .global - This indicates that the code below can be called from anywhere and/or is available globally.
  • .balign - This is called the Byte align operation and is required for aligning memory and is required when you are writing into register/memory areas so that the data aligns properly. For eg:- .balign 8 aligns the underlying operation by 8 Bytes.
  • .space - This operation is used for allocating memory in bytes. For eg:- .space 4096 allocates 4KB of memory.

Please note that this only helps you in reading through the piece of code. It is recommended that you go through the RISCV ISA Specification and this introductory lecture from Berkeley EECS for more detailed explanation.

Acknowledgements

• OVPsim and SPIKE for their contributions to RISCV without which this tutorial would never have been possible.

• Sanjay A Menon for creating this tutorial.

• All employees at Valtrix Sytems for their valuable feedback and help.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

To be added.

TODO

• Create a way to run the same code on OVPsim.
• Add more tutorial code.
• Code cleanup