MICRO2 UsersGuide Jun79

This document is a user's guide and reference manual for the MICRO2 assembler, a tool designed to convert microprograms written in its source language into absolute object code.

Key functions and features of MICRO2 include:

1. Translation: It translates symbolic names (for fields and their values within a microword) into the appropriate bit sequences, performing syntax and validity checking in the process.
2. Address Selection/Allocation: It assists in assigning addresses to microinstructions, supporting both sequential and random allocation methods. Users can define address spaces, specify constraints for address selection (e.g., for conditional branching), and manage multiple distinct memory regions within a single program (up to seven sub-programs or "memories").
3. Symbolic Definitions: Users can define field names for specific bits within a microword and assign value names to represent specific bit patterns for those fields. Qualifiers can be added to fields for default settings, parity adjustment, or validity expressions.
4. Macros: It provides a macro capability for creating higher-level abstractions of microprogram operations, replacing macro names with their defined field-settings or nested macro-calls, thereby improving readability and maintainability.
5. Expressions and Validity Checking: Supports various expressions (numbers, names, function calls, predefined symbols) and allows associating validity expressions with fields and value names to ensure legal usage, issuing warnings if conditions are not met.
6. Microinstruction Processing: Describes how MICRO2 constructs a microword, including initializing counters, setting explicit fields, applying defaults, evaluating validity expressions, and performing parity adjustments.
7. Program Identification & Structure: Directives allow users to provide titles, version numbers, tables of contents, page breaks, microword width specifications, and comments to enhance program organization and readability.
8. Communication: Facilitates communication between different memories within the same program and between separate microprograms loaded into a control store.
9. Conditional Assembly: Allows for the conditional inclusion or exclusion of parts of a microprogram during assembly based on the evaluation of expression-names.
10. Output Listings and Controls: Produces detailed output listings, including a table of contents, line numbers, page headings, microword information (object code), error messages, cross-reference listings, and memory maps. Users can control the format and content of these outputs.

The manual is intended for assembly language programmers and hardware engineers familiar with microprogramming and relevant architecture. It details the language constructs, identification methods, field and macro definitions, microinstructions, allocation, conditional assembly, output controls, and how to use MICRO2 in VAX/VMS, DEC 10, and DEC 20 environments.