JiTBoy is a project and paper that explores JIT Binary Translation as an Accelerated Means of Emulation. It contains an interpreter, a JIT emulator, and a hybrid emulator for emulating MIPS-1 binary on x86 CPUs running Windows.

Paper

The paper written about JiTBoy can be found here

Build Instructions

The JiTBoy project can be built by building the solution JiTBoy.sln either through Visual Studio 2019 or with MSBuild. JiTBoy has two different build configurations that can be used:

Configuration	Description
Debug	Debug builds enable debugging in addition to producing more detailed logs of the emulator execution, but the performance is significantly worse. Use Debug builds for running single tests or investigating test failures and errors.
Release	Release builds give the highest performance but take longer to build; furthermore, no logs are produced from release builds. Use Release for running mass tests or collecting performance data.

Usage

JiTBoy can be run by executing JiTBoy.exe in a command line interface (CLI) such as cmd. The executable will be in either Release or Debug depending on which configuration the project was built with. By default, JiTBoy will run all tests on all emulator configurations with no performance data collected. To collect performance data, provide one of the following --timing arguments

Argument	batch_size	threshold	precision
--timing=none	1	0	1
--timing=fast	1	2	0.1
--timing=accurate	10	10	0.01
--timing=final	100	10	0.0001

JiTBoy can also be run on a single test with an emulator config of choice by using --single; it is recommended to build with the Debug configuration for improved logging. To use --single, invoke JiTBoy with the following format:

JiTBoy.exe --single test_path emulator_config

test_path must be a relative or absolute path to the test file desired. If a normal assembly file is provided, then no test validation will be performed. emulator_config must be one of the following emulators:

Emulator	Argument Options
JIT	-L Enables direct linking
Hybrid	-L Enables direct linking -S Enables speculative compilation -Tx Sets the compilation threshold to x
Interpreter	None

The emulator config is case insensitive. For example, the following would invoke the test long_mul.s under the JIT emulator with direct linking enabled:

JiTBoy.exe --single tests/mips/func/long_mul.s JIT -L