Too Long; Didn't Read
We talk about some of the open source FPGA tools which are currently available now. The discussion looks at 4 different types of open source software tools - simulators, synthesis tools, place and route software and finally tools which can be used to build a bitstream. GHDL and icarus verilog are the most popular open source simulators. For a complete open source toolchain, it is recommended to use the yosys synthesis suite together with the nextpnr place and route tool.