A tale of binary translation

This repo contains the code for the RISC-V emulator that I presented at Rust Nation 2023.

It is intended as a teaching example to introduce people to the principles behind binary translation, and not a proper production-ready emulator. However, pull requests are still welcome!

Building the examples

A build.sh script is provided in the examples directory to build the assembly code examples used in the presentation. This requires clang and llvm-objcopy to be installed. Pass the name of the assembly file to the script to build it.

The resulting .bin file can be passed as an argument to the emulator:

examples/build.sh examples/hello_word.s
cargo run -- -b interpreter examples/hello_world.bin

System calls

The behavior of the ecall and ebreak instructions is defined in syscall.rs. Currently, ebreak will stop the emulator and exit the process. ecall invokes a system call depending on the value of x17:

System call number (x17)	Name	Description	Arguments	Return value
0	`print`	Prints a string	x10: string address x11: string length
1	`print_int`	Prints an integer	x10: integer to print
2	`get_arg`	Returns the Nth argument as an integer, or 0 if absent	x10: argument index	x10: argument value

You can easily define additional system calls by extending syscall.rs.

License

Licensed under either of:

Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.