FPGAsm
Create fast bare-metal FPGA designs without Verilog or VHDL
...Now you can focus on learning the ins and outs of the FPGA instead of complex tools and languages.
Fast turnaround time and bottom-up approach invite exploration, experimentation, live circuit testing and physical test harness creation, radically changing the workflow.
FPGAsm offers you an opportunity to REALLY understand Xilinx FPGAs, create circuits DIRECTLY on the FPGA using an opensource tool, and share your knowlege and projects with the community.
Supported architectures:
Xilinx (via xdl)