BeagleBoard/GSoC/2021 Proposal/simpPRU Improvements

=Proposal for Improvements to simpPRU =

About
Student: Archisman Dey Mentors: Abhisekh Code: https://github.com/VedantParanjape/simpPRU Wiki: https://elinux.org/index.php?title=BeagleBoard/GSoC/2021_Proposal/simpPRU_Improvements GSoC: [N/A]

=Status= This project is currently an unfinished draft proposal.

=Proposal= I have completed all the requirements listed on the ideas page. The code for the cross-compilation task can be found here, submitted through the pull request #146

About you
IRC: archismandey (@archismandey:matrix.org) GitHub: GitHub Account School: Indian Institute of Technology Guwahati Country: India Primary language: English, Bengali, Hindi Typical work hours: 10:30 AM - 8:30 PM US Indian Standard Time Previous GSoC participation: This is the first time I am participating in GSoC.

About your project
Project name: Improvements to simpPRU

Description
This project aims to improve simpPRU, the simple python-like language developed during GSoC 2020 to make programming the PRU easier, by doing the following things:

Add suport for BeagleBone Blue Currently, simpPRU supports the following boards: PocketBeagle, BeagleBone Black, BeagleBone Black Wireless and BeagleBone AI. This project will add support for the BeagleBone Blue (solving issue#4). Adding support for other boards in the BeagleBone family like the SeedStudio boards can also be done depending on availability. This will be done by adding the pin mappings for the BeagleBone Blue in include/pin_config.h, and setting the device model in src/pin_config.c.

Add unit tests Currently, simpPRU lacks any testing apart from making sure the examples work. This project will add unit tests for every feature present in simpPRU.

For example, a test case for variable assignment, equality checking, and if statement would look like: int a := 5; if : a != 5 { error; } return 0; Then we would build and run using the host C compiler and make sure that error never gets called.

For the PRU specific functions, a stub function will have to be provided to satisfy the linker, for example: void digital_write(pin_number, value) { printf("Digital Write called"); }

Running the unit tests would be automated into the build process.

Update the grammar so that control statements (break/continue) can only be called inside loops Currently, they can be called inside any compound statement such as conditionals, which will throw an error while compiling the generated C code. After updating the grammar, this would be an error in the bison parser.

Update the grammar so that return statements can be called anywhere in the function Currently they can be called only at the end of a function, which is less flexible.

Add a more flexible for loop Currently the for loop in simpPRU can only handle loops of the form for : var in range_1:range_2 {...}, where range_2 > range_1

This project will add support for more flexible for loops of the form for : var in range_1:range_2:increment {...}, where range_1, range_2, and increment can be any integers.

Better error handling in the parser simpPRU has some error handling in the bison parser, but it is not comprehensive. This project will add more comprehensive error handling.

Possible idea, to be added: Considering possiblities and approaches about sending denser information through rpmsg since currently simpPRU only supports sending one integer at a time, and Linux kernel will not be able to handle, for example, one integer every 100 microsecond. The solution is to store the integers in the PRU memory and send a list of int to the host through rpmsg every 10 ms (for example). Also, while simpru-console is very easy to use, it is not easy to automate. It could be helpful to implement a Python library exposing functions defined in simppru-console.
 * Bonus: Add support for calling C code from simpPRU: This can be done if time is left after the other tasks are completed. Approaches will have to discussed with mentors.

Timeline
(will make a more detailed timeline later)

Experience and approach
I have some experience with building stuff using arduinos and other controllers before (github). I also have programming experience with C, C++, and Python. I got interested in how parsers and compilers work while trying to build a symbolic differentiator (github) as a personal project. I have learned the basics of how flex and bison work and looked at the repository for simpPRU and I understand how it works. So I think I am qualified to work on this project.

Contingency
BeagleBoard is a very active community and it is unlikely that none of the mentors would be willing to help. That said, everything I am going to be working on is an open source project with good documentation, so I will use all the resources available to help myself.

Benefit

 * quotes

Misc
Link to pull request: #146