A fast FPGA based coprocessor supporting hard real-time search

In their work on dual port memories S. Cittolin and A. Fucci et al. (1995) describe a design approach for programmable message driven multi port memories (DPMs) with a high throughput (100 MByte/s). The design for nearly sequential requests (typical for some data acquisition systems (DAC)) causes accessing problems for more general applications. Considering hard real time requirements of DAC systems, the paper proposes two hardware implemented (based on FPGA technology) coprocessor architectures for searching in the file descriptor table of the dual port memory and compares them according to implementation costs and performance. Additionally the used searching strategy was implemented on the TI DSP C40 and the performance was compared to the hardware implementation. The examined hardware strategy is independent from the rest of the dual port memory and can therefore also be integrated into other computer systems as a generic searching coprocessor.