Digital-7-92-M

This document outlines "Part 1" of a diagnostic program for the PDP-4/7 computer's Extended Accumulator and Extended Arithmetic Element (EAE). The primary purpose of this diagnostic is to verify the correct functioning of all EAE operations, with the exception of multiplication and division. A minimum PDP-4/7 configuration with the EAE option is required.

The diagnostic is structured into three logical sections, designed to be run incrementally:

1. Set-Up Test: Verifies the correct operation of all EAE set-up functions, excluding the LACS instruction.
2. SC (Shift Counter) and Basic Shift Test: Confirms the proper operation of the Shift Counter (including LACS) and ensures that the Accumulator (AC) and Multiplier-Quotient (MQ) registers can perform single-place left and right shifts across all 18 bits.
3. Random Data, Normalize, and Interrupt Test: Checks the ability to shift random data by 0 to 448 places, verifies the correct execution of NORM and NORMS instructions, and confirms that the teleprinter flag generates an interrupt following an EAE operation.

Upon detecting a hardware malfunction, the program generates a detailed error message on the teleprinter and halts the processor. These error reports provide crucial information, including the fault address, the mnemonic of the operation being tested, the initial and resultant register contents, and the expected outcomes, facilitating troubleshooting. The document also describes various switch settings that control the program's error reporting behavior and test repetition.