v7's canonical integer byte-order was confirmed little-endian by
inspecting merkle-agi-dag_v7.txt §A1 — every to_bytes / astype in the
TLV encoding is little-endian (TLV length prefixes to_bytes(4,'little'),
enc_int to_bytes(8,'little'), quantized tensors '<i8'); no big-endian
anywhere. Per dav1d's 2026-05-11 review rule ("if v7 TLV canonical
integer encoding is little-endian, flip §3.4 to little-endian before
KAT freeze"), flip done — this is the -le variant.
Implementation (arborist/substrate/anchor_prg.py):
- PHI_PRG_VERSION → "phi-prg-v1-hmac-sha512-le" (still "v1";
the -le suffix records the endianness; future re-flip MUST bump).
- _expand: counter.to_bytes(4, 'big') → 'little'.
- _bytes_to_floats: int.from_bytes(..., 'big') → 'little' (the
uint32-word interpretation, for full consistency with v7).
- Module + function docstrings updated: little-endian throughout,
with the merkle-agi-dag_v7.txt §A1 verification note.
- Note: at counter=0 the bytes are identical regardless of
endianness, so 5 of the 10 KAT entries (dim_h ≤ 16, single block)
keep the same output_sha256; the 5 multi-block entries (dim_h 17/
32/64×3/4096) change.
KAT fixture (bench/fixtures/phi-prg/known-answer-tests.jsonl):
- Regenerated under the little-endian counter. Each entry now also
carries a "version" field (phi-prg-v1-hmac-sha512-le). Header
comment updated.
Tests (tests/test_anchor_prg.py, 30 → 31):
- test_module_exports_version_string: assert the -le suffix.
- test_bytes_to_floats_midpoint_maps_to_zero: 2^31 is b'\x00\x00\x00\x80'
in little-endian, not b'\x80\x00\x00\x00'.
- New test_bytes_to_floats_reads_little_endian: pins the byte-order
so an accidental re-flip is caught.
- test_phi_prg_first_block_matches_direct_hmac: uint32-word reads
little-endian (counter=0 bytes unchanged either way).
- test_phi_prg_known_answer_tests: assert kat['version'] == module
version when present.
Spec text (#000035 §3.4): folded the little-endian variant of
dav1d's §9.10 wording — counter_le32, uint32_le word reads, an
"all integers little-endian, matching v7 TLV §A1" preamble, and an
"Endianness — RESOLVED 2026-05-11" note replacing the open
big-vs-little question. soft-hash-channel-analysis.md §9.2/§11 +
#000035 status + TICKETS.md row updated. AUTOCOUNT for
test_anchor_prg.py bumped 30 → 31; PHI_PRG_VERSION refs in docs
bumped to -le.
Full suite: 2312 passed, 28 skipped.
russell@unturf.com
101b101281