Slowcref

Summary

SLOWCREF is a specialized cross-reference program designed for the PDP-12 computer, created as a modification of the standard CREF 12 utility. It is intended for use with the LAP6-DIAL-MS assembly system, specifically to handle the cross-referencing of large system programs that exceed the capacity of the standard CREF 12 program. By utilizing a 16K memory configuration, SLOWCREF can accommodate larger programs, though it operates significantly slower (4 to 8 times) than the original CREF 12.

Key features and operational details include:

• Usage: It works in conjunction with the LISTAPE pseudo-op within the DIAL-MS assembler, which writes the assembly listing to a scratch tape or disk.
• Requirements: The program occupies six blocks of memory and requires specific sense switch settings and user input (unit number, printer/teletype selection) to generate an alphabetical listing of user-defined symbols and their line numbers.
• Limitations: SLOWCREF includes error handling for assembly errors and memory overflows. If the symbol table exceeds its capacity—determined by the number of user-defined symbols and total references—it will terminate with a "CORE OVERFLOWED" message.
• Coding Recommendations: The documentation advises users to employ symbolic references (for registers and core locations) and to avoid large displacements from tags to ensure the most accurate and useful cross-reference output.
• Internal Structure: The document provides a technical breakdown of the program’s subroutines (e.g., SYMBUILD, SCAN, DUMP), explaining how the program parses the assembler listing, constructs the symbol table, and formats the final cross-reference report.