Hardware Processing Engines#

Hardware Processing Engines (HWPEs) are special-purpose, memory-coupled accelerators that can be inserted in the SoC or cluster of a PULP system to amplify its performance and energy efficiency in particular tasks.

Differently from most accelerators in literature, HWPEs do not rely on an external DMA to feed them with input and to extract output, and they are not (necessarily) tied to a single core. Rather, they operate directly on the same memory that is shared by other elements in the PULP system (e.g. the L1 TCDM in a PULP cluster, or the shared L2 in PULPissimo). Their control is memory-mapped and accessed through a peripheral bus or interconnect. HW-based execution on an HWPE can be readily intermixed with software code, because all that needs to be exchanged between the two is a set of pointers and, if necessary, a few parameters.


Fig. 1 Template of a Hardware Processing Engine (HWPE).#

This document defines the interface protocols and modules that are used to enable connecting HWPEs in a PULP system. Typically, such a module is divided in a streamer interface towards the memory system, a control/peripheral interface used for programming it, and an engine containing the actual datapath of the accelerator.