Digital's DECchip 21066: The First Cost-focused Alpha AXP Chip

The DECchip 21066 microprocessor is the first Alpha AXP microprocessor to target cost-focused system applications and the second in a family of chips to implement the Alpha AXP architecture. The chip is a 0.675-micrometer (μm), CMOS-based, superscalar, superpipelined processor that uses dual instruction issue. It incorporates a high level of system integration to provide best-in-class system performance for low-cost system applications. The DECchip 21066 microprocessor integrates on-chip, fully pipelined, integer and floating-point processors, a high-bandwidth memory controller, an industry-standard PCI I/O controller, graphics-assisting hardware, internal instruction and data caches, and an external cache controller. Cost-saving packaging techniques and an on-chip, analog phase-locked loop enable the chip to meet the cost demands of personal computers and desktop systems. This paper discusses the trade-offs and results of the design, verification, and implementation of the DECchip 21066 microprocessor.