Venus IBOX.MCR

This document is a detailed technical listing and documentation for the VENUS Ibox Microcode, Version V3.73, authored by John DePosa and dated May 7, 1984.

The document provides a comprehensive overview of the Ibox microcode, including:

• Revision History: A detailed log of changes and updates to the microcode from August 1980 to June 1984.
• Microword Definition: Specifications for the Ibox microword structure, including definitions for "Dummy Fields" and "Real Fields," along with associated notes and restrictions.
• Microcode Macros: Definitions for both "Diagnostic" and "System" level macros used in the microcode.

• Core Microcode Routines: The bulk of the document details various microcode routines, such as:

  • The "Ifork Vector," which serves as the primary dispatcher for different operand specifier routines.
  • Various "Microtraps" designed to handle unaligned memory accesses, Ebox commands, and master reset operations.
  • Routines for specific addressing modes, including Rn, (PC)+, Literal Specifiers, and Indexed addressing.
  • Common "Fetch Phase" and "Indirect Address Fetch" routines.

• General Description: An overview of the microcode's overall structure and how different components interact.

• Cross Reference Listing: A comprehensive index of all defined field names, macro names, and their corresponding line numbers throughout the listing.
• Assembly Summary: A final page summarizing the I-code microword memory usage (173 words used out of 173 possible) and the assembly process results (0 warnings, 0 errors).

In essence, the document serves as a complete technical specification, source code listing, and operational guide for the VENUS Ibox Microcode.