DDT Manual Apr86

This TOPS-10 DDT Manual (AA-BH82B-TB, April 1986) describes the use of DDT V44, the Dynamic Debugging Tool, for debugging MACRO-10 programs on TOPS-10 V7.03.

The manual outlines DDT as an interactive utility for:

• Finding Errors: Interrupting program execution at breakpoints to examine and modify memory (instructions and data).
• Analyzing Control Flow: Executing instructions one-by-one (single-stepping) to verify intended effects.
• Symbolic Debugging: Using program-defined symbols instead of absolute addresses for easier referencing.
• Patching: Inserting and testing new series of instructions without reassembling the program.
• Advanced Operations: Searching for data patterns, manipulating symbols, and controlling program execution.

It details various DDT variants tailored for specific tasks:

• DDT.REL: Relocatable version merged with user programs via the DEBUG command.
• DDT.EXE: Stand-alone version for direct MACRO-10 instruction testing.
• VMDDT.EXE: Merged with programs via the DDT command.
• FILDDT.EXE: For examining and modifying disk files, disk structures, monitor crash dumps, and other running jobs.
• EDDT.EXE: For debugging and patching the monitor in executive or user mode.

The document covers command syntax, expressions, display modes, memory manipulation, program execution control, symbol management, patching techniques, and physical/virtual addressing commands, including those for extended (non-zero) sections. It also includes an appendix of error messages and a glossary of terms.