KE44-A CISP

This document serves as a user's guide for the KE44-A Commercial Instruction Set Processor (CISP) option, which enhances the commercial data processing capabilities of the PDP-11/44 computer. The KE44-A integrates into the KD11-Z Central Processing Unit, providing a specialized Commercial Instruction Set (CIS) for efficient manipulation of byte strings, character data, and decimal string operations, crucial for applications like COBOL, text editing, and word processing.

The KE44-A hardware consists of two main modules: the M7091 Control Store board, which contains the microcode implementing the CIS instructions, and the M7092 Data Path board, which houses the operational logic. It operates in two modes: a slave (idle) mode, where it monitors for CIS instructions, and a master mode, where it takes control to execute received CIS operations. The guide details the installation procedure for these modules, including switch settings, and outlines a diagnostic checkout process using the CZKEEA instruction exerciser to verify functionality across various system conditions.

A significant portion of the document describes the KE44-A's internal architecture, broken down into four functional areas: Instruction Register (IR) Decode, CIS Program Counter (CPC), and Microprocessor Counter (MPC) Addressing; Binary Data Path; BCD Decimal Data Path; and Status Information and Condition Code Generation. These sections explain how instructions are decoded, data is processed (both binary and Binary Coded Decimal (BCD) nibble data), and how system status and condition codes are generated.

The guide also provides an in-depth explanation of the extended instruction data types supported by the CIS, including characters, character strings, character sets, and various decimal string formats (packed, zoned, overpunch, separate) and their descriptors. It also covers long integer data types.

The core of the document is a comprehensive definition of numerous CIS instructions, such as decimal arithmetic (Add, Subtract, Multiply, Divide, Arithmetic Shift), character operations (Compare, Locate, Match, Move, Move Reverse Justified, Move Translated, Scan, Skip), and data conversion between long integers and decimal strings. Each instruction definition includes its format, operational details, how it affects condition codes, its suspendability (ability to be interrupted), a detailed description of its function, and practical examples for both register and in-line forms. Appendices provide lists of CIS abbreviations and CISP mnemonics for reference.