Source: https://twitter.com/mach_kernel

And a last one regarding the Apple IIgs for today. One of the most fundamental pieces of software that you need on a computer, is an editor. No matter what, just an editor and an assembler make a system really independent from cross-assemblers.

However, implementing an editor is easier said than done. Ask David Stancu. He did it. And he did it on an Apple IIgs.

What a feat. David decided to implement mrbuffer purely in assembly. There are other options, but he actually wanted the MOS 65618 to run in real 16-bit mode, and ditched the idea of C compilers for the 6502 compatibility mode.

In this article David goes into all the gory details of the memory map, video RAM, character display and the necessary architecture for an editor.

A very nice read for everyone, who still enjoys some 65xx assembly.