After the BUILD 2020 conference, Microsoft released the source code for GW-BASIC, a spruced up version of the product that put the company on the map. Although disassembled versions of various versions of Microsoft BASIC can be found online, this historical artifact contains the original comments and provides an interesting insight in how the computing landscape changed during the late 70s and early 80s.

The provided code is for the Intel 8086 processor, but it was mechanically translated from the original code for the Intel 8080 processor. This is evidenced by many comments referencing registers and features not present in newer CPUs, as well as a comment at the beginning of every source code file stating that it was mechanically translated.

This talk will present an effort to convert it back to the Zilog Z80 processor, which is compatible, at a machine code level, with the Intel 8080. It'll talk about the process that lead to the creation of a tool that translates the instructions, how it came to be, the current state, and how you can get involved.