JMP Y - Interrupt Test

This document details the JMP Y - Interrupt Test for the PDP-9 computer, designed to verify that the system completes a JMP Y instruction (where Y is a random value) before entering a program interrupt. The test achieves this by setting an I/O flag and then transferring control to a randomly located ION/JMP Y instruction group in memory. The expected behavior is for the JMP Y instruction to complete without interruption. If the instruction executes successfully, the instruction group is moved to new random memory locations, and the test is repeated. Errors are communicated to the operator via the Teletype or through program halts.

The program requires a standard PDP-9 computer and utilizes its entire 8K memory, with the program itself occupying locations 17400 to 17733 and testing all locations below 17400. It necessitates the prior execution of Instruction Test Parts 1 and 2 (MAINDEC 9A-D01A-D and MAINDEC 9A-D02A-D). Loading involves placing an HRI tape in the reader, setting ADDRESS SWITCHES to 17400, and depressing the READ-IN key. Starting the program involves setting ADDRESS SWITCHES to 17400, configuring ACCUMULATOR SWITCHES (normal setting 500000) for desired error handling and looping behavior, depressing I/O RESET, and then START. Errors trigger specific halts or Teletype messages, and recovery procedures are provided. The test takes approximately 96 milliseconds per ION/JMP Y instruction group.