Getting Started

With FPGRARS and RISC-V assembly

In this guide, we'll go over the basics of running RISC-V assembly programs with FPGRARS!

Installation

If you haven't yet downloaded FPGRARS, head over to the latest release and download the appropriate executable. The easiest way to "install" it is by putting it in the same folder as our assembly file:

my-wonderful-riscv-project
|- fpgrars-executable
|- riscv.s

If you later want to use FPGRARS for multiple projects, it's best to put the executable in a folder that's in your PATH environment variable (could be ~/.local/bin for Unix, idk where for Windows sorry /shrug).

If you have the Rust toolchain installed, you can also download FPGRARS by running cargo install fpgrars.

Hello World!

Create a riscv.s file and put the following content in it:

riscv.s

.data
# Define the label "hello" to as the address to the very start
# of the "Hello World!\n" string 
hello: .string "Hello World!\n"

.text
    li a7, 4     # Load 4 (the ecall for "print string") into the a7 register
    la a0, hello # Load the address of the label 'hello' into a0
    ecall        # Perform an environment call

    li a7, 11    # Load 11 ("print character" ecall) into a7
    li a0, '\n'  # Load '\n' into a0
    ecall        # Perform an environment call

    li a7, 10    # "exit" ecall
    li a0, 0     # exit with code 0 
    ecall

You can now run the program with the command ./fpgrars riscv.s and you should see a "Hello World" appear on your terminal!

Note that ./fpgrars should have the full name of the executable file. On Windows, it's probably something like ./fpgrars-x86_64-pc-windows-msvc--original.exe, on Linux, ./fpgrars-x86_64-unknown-linux-gnu--original. Of course, you can rename it to whatever you want, like just fpgrars.

Using the Bitmap Display

This section is WIP :)

While I'm working on that, check out the samples folder! There are many examples there that may help you. I guess keyboard_and_display_demo.s is the easiest to follow, but polygon.s is definitely the coolest.