The Intel 80386, part 1: Introduction – The Old New Thing

Submitted by michael on Tue, 01/22/2019 - 11:39

The Intel 80386 is the next step in the evolution of the processor series that started with the Intel 8086 (which was itself inspired by the Intel 8080, which was in turn inspired by the Intel 8008). Even at this early stage, it had a long history, which helps to explain many of its strange corners.

As with all the processor retrospective series, I'm going to focus on how Windows NT used the Intel 80386 in user mode because the original audience for all of these discussions was user-mode developers trying to get up to speed debugging their programs. Normally, this means that I omit instructions that you are unlikely to see in compiler-generated code. However, I'll set aside a day to cover some of the legacy instructions that are functional but not used in practice.

Amazing look at the history of a single CPU. I wish I knew enough about hardware to really understand this article.