21264/EV68A Microprocessor Hardware Reference Manual

This document is the Hardware Reference Manual for the Compaq 21264/EV68A Microprocessor, published in March 2002. It is intended for system designers and programmers who work with this specific Alpha architecture microprocessor.

The manual provides comprehensive technical details across various aspects of the chip, including:

• Architecture Overview: An introduction to the Alpha architecture and the specific features of the 21264/EV68A microprocessor.
• Internal Architecture: Detailed descriptions of major hardware functions, microarchitecture (e.g., instruction fetch/issue/retire units, integer and floating-point execution units, on-chip caches, memory reference unit), pipeline organization, instruction issue rules, and performance measurement support.
• Hardware Interface: Specifications for signal names, functions, pin assignments, mechanical data, and packaging.
• Cache and External Interfaces: Information on external bus functions, transactions, cache coherency, and clocking.
• Internal Processor Registers: A listing and description of the chip's internal register set.
• Privileged Architecture Library (PALcode): Details on the software layer that provides operating system primitives and low-level hardware access.
• Initialization and Configuration: Guidance on power-up reset flows, fault resets, sleep modes, and array/interface initialization.
• Error Detection and Handling: Mechanisms for identifying and managing various hardware errors.
• Electrical and Thermal Data: Electrical characteristics, power supply considerations, and thermal management specifications for the processor.
• Testability and Diagnostics: Features designed to support chip and system-level testing.

In essence, it serves as a complete technical reference for understanding the functional, electrical, and operational characteristics necessary for integrating and programming systems based on the 21264/EV68A microprocessor.