8086 Microcode Browser

https://nand2mario.github.io/posts/2025/8086_microcode_browser/

Comments

djmipsDec 4, 2025, 10:58 AM
It would be fun to step through some 8086 code at the microcode level.
ajennerDec 4, 2025, 8:19 PM
I wrote a program called xtce-trace (https://www.reenigne.org/software/xtce_trace.zip ) to do just this (albeit non-interactively - you just give it a program and it will generate a cycle-by-cycle trace of which lines of microcode are executed). GloriousCow aka Daniel Balsom recently fixed some of its bugs and turned it into an actual emulator (https://github.com/dbalsom/XTCE-Blue ), though it's not finished yet so there's no binary release at the moment.
nand2marioDec 5, 2025, 2:29 AM
xtce_trace sounds fantastic — exactly what I need right now while debugging my Verilog 8086 core. Thank you also for the microcode disassembly. It’s been fun to work through.