DEC OSF/1 Assembly Language Programmer's Guide

This document, published in February 1994 for DEC OSF/1 Version 2.0 or higher, serves as a comprehensive guide for experienced assembly language programmers targeting Alpha AXP systems. It describes the assembly language, its syntax rules, and how to write assembly programs.

The manual covers fundamental architecture-based considerations such as registers (integer and floating-point), bit and byte ordering (little-endian), addressing schemes (aligned and unaligned data operations), and various exceptions. It details lexical conventions for writing assembly code, including comments, identifiers, constants, statements, expressions, and address formats.

A significant portion of the guide is dedicated to the instruction sets:

• Main Instruction Set: Covers load and store, arithmetic, logical and shift, relational, move, control, byte-manipulation, and special-purpose instructions.
• Floating-Point Instruction Set: Describes floating-point data types, the floating-point control register, exceptions, rounding modes, and specific load and store, arithmetic, relational, move, control, and special-purpose instructions.

The document also explains assembler directives for various bookkeeping, storage reservation, and control functions. It provides programming considerations, including calling conventions, the program model (executable images, shared libraries), register usage, stack frames, and how to interface assembly code with high-level languages. Finally, it delves into the structure and processing of object files, including headers, sections, various object file formats (OMAGIC, NMAGIC, ZMAGIC), program loading, dynamic linking, and symbol table management, with appendices summarizing all instructions and 32-bit considerations.