This project is a simulator for a hypothetical RISC-V based game console. The repository provides Dockerfiles to build the necessary RISC-V toolchain for firmware and/or "game" development. The simulator was developed for use in UC Davis' Computer Science courses; however, any other educators are highly encouraged to take this repository and modify it to meet the needs of your class.
The simulation environment and toolchain have been setup to run within a Docker container. The directions assume that you have git, Docker, X-11 support and a bash shell on your machine. If you are running on Windows and wish to use PowerShell follow the directions here.
The code is available on github. Assuming you have ssh setup for git start by cloning the repository with the following command:
git clone [email protected]:UCDClassNitta/riscv-console.git
You should see something like:
Cloning into 'riscv-console'...
remote: Enumerating objects: 176, done.
remote: Counting objects: 100% (176/176), done.
remote: Compressing objects: 100% (111/111), done.
remote: Total 176 (delta 71), reused 163 (delta 63), pack-reused 0
Receiving objects: 100% (176/176), 694.17 KiB | 3.71 MiB/s, done.
Resolving deltas: 100% (71/71), done.
Once the repository has been cloned, change directories into the riscv-console and run the console launch script with the command:
./rvconsole.sh
The script will pull the base RISC-V Docker image cjnitta/riscv_base that has the RISC-V build tool chain. This will take some time as the image is several GB in size. This should only have to be done once. Once the base image has been pulled the RISC-V development environment Docker image riscv_console_dev will be built. The second image builds upon the base and should build quickly. Once the image is built the script will launch a container name riscv_console_run. This will mount the current riscv-console directory into the /code directory of the container allowing for source files to be edited on the host machine as well as within the container. Once the container is launched you should see a prompt like:
root@fedcba9876543210:/code#
The next step is to build the RISC-V example program to test on the simulator. Change directory into /code/riscv-example and then run make. This should build an example that will put Hello World! on the simulator screen and have an X that will move based upon the controller direction buttons.
You can launch the simulator with the full path using the command:
/code/runsim.sh
This should build the simulator if it hasn't been built yet and will launch the simulator using X11 assuming everything is installed properly. The script will launch the simulator under the docker user instead of root. This may be necessary for Linux clients. You should see the simulator window that looks like:
You can now select the example program by hitting the Firmware button and navigating to the /code/riscv-example/bin directory. Either the riscv-console-example, or riscv-console-example.strip file can be loaded. Once the PWR button can be pushed and the Hello World! message with an X should appear on the screen. Pressing the direction buttons on the simulator or the associated keys should move the X in the particular direction. The simulated CPU can be shut down by hitting the PWR button again. This should dump the status of the registers and memory so may take a while. Once the simulated CPU is shutdown the PWR button will no longer be highlighted. The simulator can be closed by hitting the appropriate close button for the window.
The simulator can also be run in debug mode by adding the -d option to the riscv-console-sim program or even to the runsim.sh script. You should see the simulator window that looks like following in debug mode:
The Run button will run the system until it is clicked again, or until a breakpoint is hit. The Step button will execute a single instruction, and the Clear button will clear all breakpoints. Breakpoints can be toggled by double clicking the associated instruction. The FW, CTR, CS, and VID buttons will jump to the Firmware, Cartridge, Chipset, and Video Memory base addresses. The GP and SP buttons jump to the memory specified by the gp and sp registers.