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What is HDL? Hard and Difficult Language. :)

This page reflects on various FPGA projects I came across.



  • Languages
    • SpinalHDL
    • Chisel
    • Google XLS
  • Simulators
    • Verilator
    • iVerilog
  • Misc
  • gtkwave


  • Alex Forencich’s Verilog Ethernet
    • This repo includes Ethernet PHY, MAC, IP, and UDP layer IPs.
    • It works on various boards.
    • THE BEST choice if you are trying to connect your board to network.
    • Written in Verilog
  • Alex Forencich’s Corundum NIC
    • This repo is a full-fledged NIC implementation including the above Verilog-Ethernet part, DMA engines, PCIe controller, interrupts, and so on.
    • A NIC has more features than a basic FPGA Ethenet solution. You need a NIC if you are working with host softwares, otherwise you should consider using the verilog-ethernet version.
    • Written in Verilog
  • TCP/IP, RoCEv2 from ETH
    • There are several papers published using this repo. It provides the basic TCP/IP and RoCE v2 stack (StRom, EuroSys‘19).
    • Personally I haven’t used this repo so I don’t have any comments.
    • Written in Xilinx HLS.



Partial Reconfiguration


Soft Cores


My Story with FPGA

Back at late 2018, I started using FPGA to do datacenter research. More specific, we used FPGA to build a disaggregated memory component, which was intended as a follow-up to our prior work LegoOS, OSDI‘18.

Along the way, our idea spin-off a bit. I started looking into building an real OS into FPGA: we tried to build sched (temporal and spacial), mm, net, and various OS functionalties into FPGA (more than a traditional FPGA shell, and other FPGA OSs that a lot of acadamic papers claim!). This experiences enriched me with all sorts of low-level FPGA knowledge. I spent quit a lot of time digging into partial reconfiguration and various hacks to avoid its limitations (see Bitstream Explained, Morphous PR, Ultrascale SSI). This FPGA OS project did not go well and we decided to suspend it.

Last update: October 7, 2020


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