Microcode Listing

This document contains a comprehensive microcode listing for the DEC PDP-10/20 processor. It provides low-level definitions for system operations, including:

• Register Usage: Mapping of internal and external registers.
• ALU and Shift Operations: Bit-level definitions for 2903/2904 ALU control, including arithmetic (multiply/divide) and shifting functions.
• Control Logic: Definitions for branch operations, dispatch tables, and interrupt handling.
• Console Program: Microcode implementation for console commands (Bootstrap, Continue, Examine/Deposit, etc.) and line interface handling (CTY/KLINIK).
• Paging: Logic for page fault handling, memory management, and paging RAM control.
• Memory Management: Procedures for memory reading/writing, instruction fetching, and handling of various CPU exceptions.

The document is essential for understanding the low-level micro-architecture and instruction execution flow of the processor.