Wrote a 3MB standalone C runner for Gemma-2B. Caught a Layer 15 hallucination drop.

Weekend experiment running Gemma-2B on bare-metal x86-64 (pure C + AVX2, zero Python/CUDA, \~3.3MB single binary). Added a simple orthogonal probe on the residual stream to see what each layer is doing.

Tested it on Taiwan's statutory VAT rate (legally 5%). Layers 0-14 stay factual, but Layer 15 suddenly collapses into the negative, and RAX spits out "15%":

Layer 14 | Truth: +0.0163 | \[0xDF28010E\]

Layer 15 | Truth: -0.0481 | \[0x72DE18A0\] <- drops below 0

Layer 17 | Truth: -0.0817 | -> Register RAX outputs tokens: '1', '5', '%。'

Raw trace, 6-page paper, and release binary here for anyone into low-level ML:

\* Web trace: https://pulsar-tracer.web.app

\* PDF: https://pulsar-tracer.web.app/PULSAR\_Technical\_Whitepaper.pdf

\* Repo: https://github.com/tomtsai28/PULSAR-ASM