I've tried to use the vhdl-board in order to extend some function using fpga-mapping. Now, using foxbone syscalls, it costs many cycles to store/read fpga registers. From my estimates (by mapping a simple adder into the fpga), I get that it takes about 900 fpga clock cycles to do one foxbone write.
Is it faster to write an assembler inline which does the transfer? In one doc page you say syscalls are faster than /dev/foxbone driver. Or are syscalls just slow because of the OS, and they're just easier to write. Moreover, since I need to load a whole lot of fpga registers, one could think of using the AXIS processor in DMA mode. I am grateful for any explanation of embedded device programming. Thank You. Mat.
