Alpha Assembly Language Guide

Summary

This document provides an overview of the Alpha instruction set and assembly language programming conventions, as formulated by the Digital Equipment Corporation. It is designed to assist with programming and porting C code to the Alpha 64-bit architecture.

Key aspects covered in the guide include:

• Data Types: Details on how the Alpha handles 64-bit and 32-bit integers, including the specific terminology for word sizes (16-bit word, 32-bit long word, and 64-bit quad word).

• Instruction Set: An overview of Alpha's simple RISC-based instruction set, covering:

  • Arithmetic Operations: Instructions for both 4-byte and 8-byte integers.
  • Loads, Stores, and Alignment: Guidance on memory access, noting specific alignment restrictions and special instructions for unaligned byte-level operations.
  • Control Flow: Mechanisms for branches, jumps, and conditional moves.
  • Floating Point: Support for IEEE single and double-precision floating-point operations.

• Programming Conventions: Established rules for register usage and stack frames, which are essential for creating code that is compatible with standard libraries, debuggers, and linkers.

The guide concludes with structural information regarding stack frames and references to more comprehensive architectural documentation.