Functional verification of a multiple-issue, out-of-order, superscalar Alpha processor-the DEC Alpha 21264 microprocessor

DIGITAL´s Alpha 21264 processor is a highly out-of-order, superpipelined, superscalar implementation of the Alpha architecture, capable of a peak execution rate of six instructions per cycle and a sustainable rate of four per cycle. The 21264 also features a 500 MHz clock speed and a high-bandwidth system interface that channels up to 5.3 Gbytes/second of cache data and 2.6 Gbytes/second of main-memory data into the processor. Simulation-based functional verification was performed on the logic design using implementation-directed, pseudo-random exercisers, supplemented with implementation-specific, hand-generated tests. Extensive functional coverage analysis was performed to grade and direct the verification effort. The success of the verification effort was underscored by first prototype chips which were used to boot multiple operating systems across several different prototype systems.