litex VS corundum

https://github.com/enjoy-digital/litex

they have tutorials, you can get compatible boards for around $20

With LiteX you can synthesize a VexRiscV processor. You can run Linux on it. The toolchain is pretty easy to use, as long as you use Xilinx Vivado to compile to gateware.

LiteX is a great example of a Python-first flow. However, they have chosen not to subordinate the scripting environment to a GUI toolchain - EDA vendors are unlikely to choose the same trade.

To lean these: https://github.com/enjoy-digital/litex, https://github.com/m-labs/migen

If you use LiteX to generate a VexRiscV system-on-a-chip, you can include an open source DDR DRAM PHY. This works on Xilinx Spartan-6, Spartan7Artix7/Kintex7/Virtex7 FPGAs, and Lattice ECP5 FPGAs. DDR/LPDDR/DDR2/DDR3 depending on the FPGA.

I am interested in trying out FPGAs for the purpose of running specific calculations more efficiently. Since the calculations themselves are quite complex, I would need to be able to program in a relatively high-level language. I've seen that designing SoC in Python is possible, for example with Litex (https://github.com/enjoy-digital/litex) or Amaranth (https://github.com/amaranth-lang/). I don't want to spend hundreds of hours learning about FPGAs, but I'm prepared to take on a challenge.

The GPU uses this: https://github.com/alexforencich/verilog-pcie . And there is an open-source 100G NIC here, including open source 10G/25G MACs: https://github.com/corundum/corundum

Well, I did build this: https://github.com/corundum/corundum

I would look into 10GbE PCS/MAC packet processors implemented under AXI Stream interfaces for example. There are open source examples https://github.com/corundum/corundum and https://netfpga.org/ .

I built my own 100 Gbps capable NIC, along with driver: https://github.com/corundum/corundum. You're welcome to ask if you have any questions, though it is quite a different animal from a 100 Mbps NIC you might have on a microcontroller.

If you're looking for resources, here's one rather comprehensive example of a high-performance FPGA design with a fully custom DMA engine and driver, that runs on both Xilinx and Intel FPGAs: https://github.com/corundum/corundum

I have no idea, but you're welcome to build the design and look at it yourself: https://github.com/corundum/corundum/tree/master/fpga/mqnic/NetFPGA_SUME/fpga. The barrel shifters are in the DMA engine, both the read DMA and write DMA engines have wide barrel shifters.

Dive right into the slack channel and introduce yourself. There is also a new contributor guide. /u/alexforencich/ is on these reddits and he may be able to chime in and give you more concrete suggestions.