The First 'Apple Silicon' : The Aquarius Processor Project - Supplemental

Apple’s first attempt to build its own processor design - using a Cray supercomputer.

We know a lot about the final Aquarius design only because a detailed document containing the Scorpius specification was made available publicly by Apple (or more likely leaked and no-one cared given the project was over by then!)

This document is a late specification, from 1989, about a year before the project was cancelled. This means that the four processors are based on the final RISC design rather than the earlier stack architecture.

So how ambitious and ground-breaking was the Scorpius project? Let’s have a look at the architecture and the instruction set.