This repository contains the specification for the CHERIoT ISA. It consists of a document written in latex which includes excerpts of the reference model written in Sail. The current draft architecture document built from this repository contains a full description of the ISA and its intended use by CHERIoT RTOS. The Sail code is used to build an instruction set simulator which is included in the CHERIoT RTOS dev container. It can also be used to prove properties of the ISA using Sail's SMT support.

The architecture is based on the CHERI specification. The code is derived from sail-cheri-riscv and uses sail-riscv as a submodule.

The easiest way to use the emulator is to use the dev container for the CHERIoT RTOS as described in the getting started guide.

Alternatively, if you wish to build from source you must first install dependencies, including Sail. For example, on Ubuntu 20.04 we have tested:

sudo apt update
sudo apt install opam z3 libgmp-dev
opam init
opam install sail

Then clone the repo:

git clone --recurse-submodules https://github.com/CHERIoT-Platform/cheriot-sail
cd cheriot-sail

Finally build the C emulator:

make csim

This will produce an executable in c_emulator/cheriot_sim that can be used to run ELF files produced by the CHERIoT compiler.

To build the documentation you must have biber, latexmk and pdflatex and have setup your opam environment as above. Then follow the following commands:

pushd archdoc
make
popd

This will create a file located at archdoc/cheriot-architecture.pdf.

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