DX20 Cross Assembler Macro

This document contains the source code and macro definitions for the DX20 cross-assembler (DX20CA), which was developed on the TOPS-20 system. It includes definitions for various instructions, memory management, addressing modes, and error handling macros essential for assembling code for the DX20 hardware architecture. The document provides detailed technical specifications for macro functionality, location counter handling, and assembly error reporting.