An object based data cache with conflict free concurrent access as shared memory for a parallel DSP

Abstract

The paper describes principle and practical implementation of an object based cache concept, allowing conflict free regular access to data structures for a cluster of processing units. The cache is based on a virtual object bound address space instead of the conventional linear address space for the access to shared data located in on-chip caches. By extending the conventional block based cache principle to 2-D blocks and using virtual addresses for address arithmetic and hit/miss detection, the time critical address calculations in the load/store pipeline can be performed fast and at low hardware cost. Transform to physical addresses is performed during block transfer between internal caches and external system memory, where it is much less time critical and must only be performed once per block. The object based cache is compiler friendly, fully transparent to the programmer, and allows the hardware efficient implementation of a shared on-chip memory system for future parallel digital image processors.