Random Isz Test

This document provides documentation for a diagnostic program designed to test the ISZ (Increment and Skip if Zero) instruction on the PDP-8 computer.

Program Overview: The program performs tests in two parts:

• Part 1: Uses a random number generator to select FROM, TO, and OPERAND locations/values to test the ISZ instruction.
• Part 2: Executes a fixed set of test conditions for more controlled analysis.

Functionality: The diagnostic verifies that the ISZ instruction correctly increments the specified memory operand and executes the appropriate skip or no-skip behavior. The program includes logic for error handling, allowing operators to halt on errors and providing detailed printouts regarding which instruction failed, the specific operand involved, and the result of the operation.

Operational Requirements:

• Equipment: Requires a PDP-8 with a Teletype.
• Storage: Uses memory locations 0000–7600 (octal).
• Setup: Operators can use switch settings (SR0–SR11) to control test parameters, such as forcing fixed constants, selecting specific parts of the test, and controlling error reporting (halt or resume).

The document concludes with a full assembly listing, including the constant/variable definitions, test logic, error routines, and a complete symbol table.