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Comment by checker659 | Hacker News Reader

I think FPGAs (or CGRAs really) will make a comeback once LLMs can directly generate FPGA bitstreams.

No need. I gave ChatGPT this prompt: "Write a data mover in Xilinx HLS with Vitis flow that takes in a stream of bytes, swaps pairs of bytes, then streams the bytes out"

And it did a good job. The code it made probably works fine and will run on most Xilinx FPGAs.

> The code it made probably works fine

Solve your silicon verification workflow with this one weird trick: "looks good to me"!

Its how I saved cost and schedule on this project.

I don't even work in hardware, and yet even I have still heard of the Pentium FDIV bug, which happened despite people looking a lot more closely than "probably works fine".

What does "directly generate FPGA bitstreams" mean?

Placement and routing is an NP-Complete problem.

And I certainly can't imagine how a language model would be of any use here, in a problem which doesn't involve language.

They are "okay" at generating RTL, but are likely never going to be able to generate actual bitstreams without some classical implementation flow in there.

I think in theory, given terabytes of bitstreams, you might be able to get an LLM to output valid designs. Excepting hardened IP blocks, a bitstream is literally a sequence of sram configuration bits to set the routing tables and LUTs. Given the right type of positional encoding I think you could maybe get simple designs working at a small scale.

I'd expect a diffusion model to outperform autoregressive LLMs dramatically.

Certainly possible! Or perhaps a block diffusion+autoregressive model or something like GPT 4o's image gen.

AI could use EDA tools

AMDs FPGAs already come with AI engines.

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