This Microsoft BASIC interpreter is written in Assembly, to no surprise considering the vintage of the software. But Microsoft did push this code through a translator in order to make use of newer x86 ISA capabilities. As such, the code being open-sourced is that derived from their original source code.
We are excited to announce the open-sourcing of Microsoft GW-BASIC on GitHub! Yes, seriously 😀 Why? Since re-open-sourcing MS-DOS 1.25 & 2.0 on GitHub last year, we’ve received numerous requests to also open-source Microsoft BASIC. Well, here we are! 😁 The Source These sources,