Development:Setting up FEX

Build dependencies

• clang
• !!! Insert remaining libraries here !!!
• x86_64-linux-gnu-g++ (For building thunks)
• nasm (only if building tests)

Build Configuration

• Ensure release mode is enabled
• Enable LTO
• Disable test building

cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Release -DENABLE_LTO=True -DBUILD_TESTS=False -G Ninja ..

ninja

Installation

sudo ninja install

On AArch64 hosts

You can install a binfmt_misc handler for both 32bit and 64bit x86 execution directly from the environment. If you already have box86's 32bit binfmt_misc handler installed then I don't recommend installing FEX's until it is useful. Make sure to have run install prior to this, otherwise binfmt_misc will install and old handler even if the executable has been updated.

sudo ninja binfmt_misc_32

sudo ninja binfmt_misc_64

Runtime Configuration

FEXConfig is the application to use for runtime configuration setup.

CTRL+SHIFT+O will open default "global" configuration.

CTLR+S saves it.

Things to ensure to set

On AArch64 host, a rootfs path is mandatory, while it is optional on x86-64 host

• Core: JIT
• RootFS
• Silent Logging (Useful to get FEX information spam out of the way)
• Block Size (500 is a good default. Optimization passes may break things though)
• Multiblock: enabled (Can cause more stuttering)
• Emulated CPU Cores: 1 (threading bugs cause issues with more)

RootFS generation

Needs to be migrated

https://github.com/FEX-Emu/FEX/wiki/Creating-x86-64-Linux-RootFS

Installing Thunks

Only if you want

https://github.com/FEX-Emu/FEX/blob/main/ThunkLibs/README.md