Cref12 Pdp-12 Cross Reference Program

This document is a technical manual for CREF12, a cross-reference program designed for the DIAL-MS environment on the PDP-12 computer. Created in July 1970, the program assists programmers in debugging and modifying code by generating an alphabetical list of all user-defined symbols, along with the line numbers where those symbols were defined and referenced.

Key features and information include:

• Operating Principles: Users are advised to utilize symbolic references for registers and constants and to avoid large displacements from tags to ensure the most useful cross-reference output.
• Requirements: The program occupies six blocks in the DIAL file area and is designed to work in conjunction with the LISTAPE pseudo-op of the DIAL-MS Assembler.
• Operational Procedures: The manual details the steps to initiate CREF12, including setting sense switches, configuring the listing unit, and selecting output options for the line printer or console Teletype.
• Error Handling: The manual describes common error conditions, such as "BAD INPUT" (often caused by assembly errors or invalid input) and "CORE OVERFLOWED," which occurs when the number of symbols and references exceeds memory capacity.
• Internal Description: The document provides a high-level overview of how CREF12 processes data, its subroutines (such as SYMBUILD, SCAN, and DUMP), and how it handles memory and file manipulation.
• Program Listing: The latter portion of the document contains the complete assembly language source code for the CREF12 program.