Per IEC 61508-3 Section 7.4.2.12 and DO-178C Section 12.1.4, this document records the qualification basis for accepting the gemmlowp fixed-point headers into this firmware as Software Of Unknown Provenance (SOUP).

Component identity

Name: gemmlowp (fixed-point subset)
Version: no upstream release tag; pinned to upstream commit 719139ce755a0f31cbf1c37f7f98adcc7fc9f425 (2018-09-04).
Upstream URL: https://github.com/google/gemmlowp
Local path: libs/third_party/gemmlowp/
- Files in tree: fixedpoint/*.h (fixedpoint.h + the per-ISA fixedpoint_{neon,sse,avx,msa}.h, all guarded by #ifdef so none is active on Cortex-M85), internal/detect_platform.h, and LICENSE. Header-only subset – the full gemmlowp GEMM machinery is NOT vendored.

Provenance

Origin: Google (gemmlowp – low-precision GEMM library).
License: Apache-2.0 (LICENSE).
How it entered our tree: vendored header subset from the upstream commit above. The exact commit is recorded by scripts/gen/sbom_registry.py and docs/sbom/upstream/gemmlowp.manifest, keeping the checked-in subset and generated SBOM under one provenance authority.

Use case in this firmware

TFLite-micro's quantized reference kernels (conv, depthwise_conv, fully_connected, softmax, ...) include fixedpoint/fixedpoint.h for saturating fixed-point rounding/rescaling math. These are the only gemmlowp facilities the vendored kernels touch.
Integrity claim category: data-handling (fixed-point arithmetic on trusted tensor data).

Qualification basis

Accepted as-is per IEC 61508-3 Section 7.4.2.12 and DO-178C Section 12.1.4:

Service history: gemmlowp's fixed-point headers are the canonical quantized-math primitives underneath TensorFlow Lite; in production across the TFLite ecosystem for years.
Open-source community process: Google-authored, open GitHub project.
Version matching: pinned to the same commit TFLite-micro vendors, so the kernels and the fixed-point headers are the version pair they were tested as.

Risk mitigation

Header-only, #ifdef-guarded ISA selection: on Cortex-M85 none of the NEON / SSE / AVX / MSA paths compile in, so only the portable scalar path is used.
Compiled behind the SOUP boundary as part of the tflite_micro object library (cmake/tflite_micro.cmake).
Exempt from the first-party gates as vendored SOUP under libs/third_party/.

Deviations / patches

None. The vendored headers are unmodified.

Last review date

Reviewed: 2026-07-10
Expected re-review by: 2027-07-10