PDP-8/E Instruction Simulators for Other PDP-8s

This document describes a collection of software subroutines designed to simulate specific non-EAE PDP-8/E microinstructions (such as BSW and various MQ operations) on earlier or different PDP-8 models. Because the PDP-8/E introduced new instructions that improved programming efficiency but broke backward compatibility, these simulators allow older systems to execute code written for the 8/E. The document details the methods used—primarily utilizing JMS links and a pseudo-MQ register—along with the advantages and limitations of the approach, such as increased memory usage and slower execution speed compared to hardware-native instructions.