Pdp-8/e Instruction Test 2

This document serves as the technical documentation and program listing for the PDP-8/E Instruction Test 2 (MAINDEC-8E-D0BB), created by Ed Fortmiller in June 1971.

Summary: This program is a diagnostic tool designed to perform comprehensive testing of the PDP-8/E computer's core instruction set and operational features. It specifically validates the following areas:

• Core Instructions: Extensive testing of Auto-indexing, Indirect Addressing, and the Deposit and Clear Accumulator (DCA) instruction.
• Processor Control: Testing of Processor IOT (Input/Output Transfer) instructions.
• Interrupt Handling: A series of tests covering interrupt logic across various instruction types (AND, TAD, DCA, ISZ, JMP, JMS, etc.).
• System Integrity: Verification of unauthorized auto-indexing and checking for proper flag management.

Operating Notes:

• Requirements: The program requires a PDP-8/E with a Teletype and occupies memory locations 0000–4416. It is intended to be run after the successful completion of the MAINDEC-8E-D0A(N) diagnostic.
• Procedure: Users load the program using a standard binary loader and begin execution at address 200.
• Error Handling: In the event of an error, the system will trigger a programmed halt. Operators can diagnose issues by using an oscilloscope or by modifying the program to loop on a specific failing test instruction.
• Feedback: The program provides an audible cue by ringing the Teletype bell approximately every 5 seconds to confirm that the diagnostic is still actively running.