From 2d69b85aa368ed7d33222792c8535fa4f5438131 Mon Sep 17 00:00:00 2001
From: Matiq <kokagishi@proton.me>
Date: Thu, 20 Aug 2026 21:09:28 +0300
Subject: [PATCH] =?UTF-8?q?P5:=20NOTES=20=E2=80=94=20F5c=20DSP-FFT=200x140?=
 =?UTF-8?q?a70=20status=20(P3=20confirmed=20unwired;=20all=20check=20targe?=
 =?UTF-8?q?ts=20PASS)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Full dsp/ check sweep green. fft.cpp = numerical radix-2 (std::cos) not bit-exact
0x140a70; split-radix butterfly + plan-gen giant + sin-table loader remain (multi-week
P3). Required only for FFT-conv byte-parity, not for the bridge renderer.
---
 handoff/NOTES_LEVEL.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/handoff/NOTES_LEVEL.md b/handoff/NOTES_LEVEL.md
index df748af..47a3771 100644
--- a/handoff/NOTES_LEVEL.md
+++ b/handoff/NOTES_LEVEL.md
@@ -1103,3 +1103,14 @@ byte parity. No code change; NOTE-only.
   RELIABLY NOT bit-exact to plugin (documented). exp2_check: 2e6 dense grid + edges,
   PASS vs std::exp2 (0 cells >1e-13) -> ensures fallback correctness only.
 Bit-exact exp2 transcription stays P3 (same bucket as DSP-FFT butterfly wiring).
+
+## ============ UPDATE 2026-08-20z: F5c — DSP-FFT 0x140a70 status (P3 confirmed) ============
+Full dsp/ check run (twin/tables/fftconv/vlog/leveltrack/levelpath/exp2): ALL PASS.
+FFT status: dsp/fft.cpp = numerical radix-2 (std::cos twiddle) used by the STFT
+framework — produces correct transform, but NOT bit-exact to the plugin DSP-FFT
+0x140a70. P3 bit-exact DSP-FFT plan: twiddle source (DAT_182616800 sin-table, sin(k*2pi/
+1024), loader FUN_180039b00 stride 2^(10-m)) + split-radix 2/4/8 in-place butterflies
+(FUN_18000bfc0/18000c5e0 with 0x8440 elementwise mul + FUN_1800437c0 acc) + plan-gen
+giant (FUN_18002f980 recursion + per-log2 factor tables) remain unwired. This is the
+multi-week gap (roadmap P3), required only for byte-parity of the FFT-conv path; the
+bridge renderer does not depend on it.