For the 8086 they had a gate level simulator called LOCIS. The problem is that intel historically designed everything at the transistor level, so the 8086 didn'

For the 8086 they had a gate level simulator called LOCIS. The problem is that intel historically designed everything at the transistor level, so the 8086 didn't map onto a gate level simulation very well. The "Coping with the Complexity of Microprocessor Design at Intel – A CAD History" paper [1] goes into details of what they used in the 80s and onwards, but it does briefly mention what they were doing before that. [1] https://www.researchgate.net/profile/Avinoam-Kolodny/publication/268005718_Coping_with_the_Complexity_of_Microprocessor_Design_at_Intel_-_A_CAD_History/links/54a13aa70cf256bf8bae6779/Coping-with-the-Complexity-of-Microprocessor-Design-at-Intel-A-CAD-History.pdf https://www.researchgate.net/profile/Avinoam-Kolodny/publica...