HP OpenVMS MACRO Compiler

This document is a comprehensive guide for software engineers tasked with porting VAX MACRO source code to HP OpenVMS Alpha or OpenVMS I64 systems. It covers:

• Porting Methodology: A step-by-step process for porting code, including how to handle VAX MACRO entry points and identifying nonportable practices.
• Compiler Operation: Differences between the VAX MACRO assembler and the new MACRO compiler, including how the compiler manages code, branching, and atomic/granular operations.
• Required Changes: Guidance on necessary source code modifications to accommodate architectural differences such as stack usage, flow control, and memory alignment.
• Performance Optimization: Techniques for improving the performance of ported code, including data alignment and branch prediction.
• 64-bit Addressing: Support and components for handling 64-bit addresses within MACRO.
• Reference Material: Detailed information on compiler qualifiers, specialized directives, built-ins, and macros specifically designed for the porting process.