Asl Setup - jljusten/tianocore GitHub Wiki
ACPI Source Language (ASL) Compiler Setup
EDK II uses ACPI to describe platform configuration and power management methods to the operating system. These methods are described using ASL, which requires an additional compiler.
ACPI Component Architecture (ACPICA) Downloads
ASL 2.0 Introduction and Overview (whitepaper @ acpica.org)
Windows
Download and install the iasl compiler by downloading the Windows Binary Tools release package. Please check to see if your project requires a specific ACPICA tools version. Place the unzipped content ("iasl.exe") into the directory "C:\ASL" on your local hard drive (create the folder "C:\ASL" if it does not exist).
Linux
Install the iasl or acpica-tools package, depending on your Linux distribution. Example for Debian/Ubuntu:
bash$ sudo apt-get install iasl