Design and implementation of a 100 MHz centralized instruction window for a superscalar microprocessor

The maxim of the superscalar architecture is that higher performance can be achieved by executing multiple instructions simultaneously. This can be realized on hardware by using a centralized instruction window. We present the design and implementation of a centralized instruction window capable of out-of-order issue and completion of four instructions per cycle. A compact layout (6.4 mm by 2.2 mm) of a 32-entry instruction window resulted from a full-custom design in 1.0 μm (drawn) 3-layer metal CMOS technology. The layout was verified by simulation and shown to operate at a clock frequency over 100 MHz