:PROPERTIES:
:CREATED:  [2026-05-24 Sun]
:ID:       13e6ae54-2d24-5aa0-b1cd-a7e8e749aa70
:END:
#+title: The Self-Driving Lisp Machine
#+filetags: :passepartout:lisp-machine:hardware:riscv:tenstorrent:

A Tenstorrent P150 (~72 RISC-V Tensix cores) running Passepartout: 72 RISC-V cores running Lisp microcode, one core dedicated to ACL2, one to Screamer, the rest to gate verification and fact store operations.

The self-driving threshold: the system can synthesize and load its own FPGA microcode or Tensix dispatch programs from within the running Lisp image. The system profiles its own gate verification latency, proposes a new microcoded instruction for the hot path, compiles RISC-V assembly from ACL2-verified specifications, loads it via PCIe DMA from within SBCL, benchmarks it — and rolls back if slower.

Every subdomain involved is software — the most codifiable domain. RISC-V ISA, SBCL internals, ACL2 metafunctions, CIC type theory, compiler optimization — all can [[id:efc76898-03f7-57ba-923d-35d65da88bb7][flip to symbolic sufficiency]] within days to weeks of ingestion.

**Timeline:** ~6,000 lines of new code (microcode, PCIe DMA, Tensix management, benchmark harness). ~60 cycles at current velocity. 2-4 weeks. Total from today: 6-10 weeks. See [[id:dc2e4f22-1c4c-5d4a-a151-f96e5d3b0d70][time estimates]] for the velocity model behind these numbers.

The Tenstorrent approach is dramatically simpler than FPGA because the microcode is RISC-V assembly (software), not FPGA bitstream (hardware with minutes-per-iteration synthesis). The [[id:1c95ce7d-a2db-506a-9608-df68f9ae211b][Lisp Machine security model]] — unified memory, tagged architecture, no MMU — applies directly because the Tensix cores share the same address space. [[id:84a537b4-4256-50c8-91f5-dd5b4538418f][Verification appliance]] economics apply: a certified Lisp Machine at scale replaces compliance hardware. See [[id:9af13fff-9725-542b-93b1-a555bc74ad72][why Lisp is economically viable now]] and [[id:29e4dbf3-cf19-589c-8b14-389e8a39d564][upgrade lifecycle]] for the economic and deployment foundations.
