CoRAM++: Supporting data-structure-specific memory interfaces for FPGA computing

Facilitating DRAM access is an essential part of an application programming environment for FPGA computing. Existing FPGA application programming environments primarily focus on support for simple, regular memory access patterns, such as block copy and streaming. This paper presents CoRAM++, a programming environment for FPGA computing that is based on an extensible set of data-structure-specific memory interfaces. CoRAM++ supports complex data structures, such as multidimensional arrays and linked lists, in addition to simple data access patterns. CoRAM++ defines an appropriate application-level interface for each supported data structure, and provides a specialized soft-logic implementation of the supporting datapath to memory. We evaluated the effectiveness of the CoRAM++ data-structure-specific approach in three application scenarios based on streams, multi-dimensional arrays and linked lists. Our results show that the CoRAM++ programming environment can offer convenient application-level interfaces without penalizing DRAM access performance.