Welcome to Pas6502 (designed and written by Paul Nicholls (…), a compiler that takes code using a dialect of Object Pascal and outputs a 6502 program by utilising the Kick Assembler cross-assembler program.
While the Kick Assembler is a cross-platform application (Java), there seems to be a Windows-specific dependency with the WinVICE and Windows-specific packaging. However, Object Pascal and 6502 – it hardly gets more 1980s style than that.
Object Pascal was the language used by Apple for all important projects during the 1980s, like LISA, Mac, etc. If not for the pure nostalgia factor, a cross-compiler may become interesting as historical source code surfaces. E.g., Al Kossow (CHM) was in the process of publishing the LISA source code. (It was under review with Apple and should have been published 2017/2018. Nothing is known about the state of affairs, The LisaList group has vanished from Google Groups in the meantime. However, there may be still hope.)