TOPS20 Coding Standards and Conventions

This document provides the official coding standards and conventions for TOPS-20 machine language source code. It covers essential practices, including:

• Statement Formatting: Guidelines on tab stops, tag placement, opcode structure, and commenting conventions.
• Comments: Requirements for extensive documentation, including proper alignment, usage of clear English, and routine header requirements.
• Listing Pages: Rules for organizing source files into pages using formfeeds and controlling flow-of-control across page boundaries.
• Macros: Standards for macro definition, usage, and indentation, emphasizing monitor-wide consistency.
• Conditionals: Procedures for indenting assembler conditionals and rules regarding angle bracket usage.
• Variables, Structures, and ACs: Guidelines for stack usage, AC mnemonics, and definitions to ensure clean, maintainable code.
• JSYS Calls: Conventions for calling monitor-call JSYSes and writing JSYS implementation routines, including entry/exit procedures and error handling.
• Subroutines: Standards for subroutine calling, argument passing, and documenting call sequences.

The guide also includes an appendix detailing how to integrate this standard into existing non-conforming code bases and recommendations for stack management.