Your Flowgraph is the Chip: GNU Radio Compiled Straight to Silicon

Abstract

Kyttar is a chip you program by drawing a flowgraph. It is a homogeneous array of small asynchronous compute cells, and a GNU Radio flowgraph maps onto it directly: a block becomes a region of cells, and a connection becomes a route between them. The graph you draw in GNU Radio Companion is essentially the layout of the design on the silicon, so there is no separate hardware-design step to manage. placeKYT is the open-source tool that does the mapping. It reads a flowgraph, places and routes it onto the array, runs it, and sends the output back into GNU Radio through custom source and sink blocks, so from the outside it looks like ordinary GNU Radio.

The harder problem is the block library. Every Kyttar block so far has been written by an AI agent. The placeKYT source includes the block-generation workflow: the prompts, the rules an agent follows to lay a block out across cells, and testbenches that check each generated block against its GNU Radio equivalent. A running knowledge base captures what works as blocks are built, so lessons learned on one carry into the next. Running unattended, the workflow has produced and verified 113 blocks, measuring each block’s quantization noise against its GNU Radio floating-point original. We instrumented 62 of those builds: a median of 232,000 tokens and 31 minutes of wall-clock time per block, and 51 of 62 verified on the first attempt.

This runs today on simKYT, a free, cycle-accurate model of the chip. A 120-cell prototype is in fabrication, with first silicon expected at the end of November 2026.