z386: An Open-Source 80386 Built Around Original Microcode

This is the fifth installment of the 80386 series . The FPGA CPU is now far enough along to run real software, and this post is about how it works. z386 is a 386-class CPU built around the original Intel microcode, in the same spirit as z8086 . The core is not an instruction-by-instruction emulator in RTL. The goal is to recreate enough of the original machine that the recovered 386 control ROM…