A 64-b quad-issue CMOS RISC microprocessor

Abstract

The HP-PA8000 is a 180-MHz quad-issue custom VLSI implementation of the HP-PA 2.0 64-b architecture delivering 11.84 SPECint95 and 20.18 SPECfp95 with 3.8 million transistors integrated on a 17.68 mm/spl times/19.1 mm die in a 3.3-V, 0.5-/spl mu/m CMOS process. Specialized clock circuits and extensive use of dynamic logic are key factors in this microprocessor's performance. Attention to clock analysis and distribution resulted in a 170 ps clock skew between any two clock nodes. This microprocessor utilizes a 56-entry instruction reorder buffer (IRE), register renaming, and dual functional units to fully exploit instruction level parallelism.