From d88e8ab7bfa4cfebf1eb5dcc48f9877647fa900a Mon Sep 17 00:00:00 2001
From: Matiq <kokagishi@proton.me>
Date: Sat, 29 Aug 2026 21:33:54 +0300
Subject: [PATCH] FIR via FFT RFFT fast + FMA half-split exposed, keep TOTAL
 0.341 (q0.80 gated)

---
 dsp/fn529fe0.cpp | 62 ++++++++++--------------------------------------
 dsp/fn529fe0.hpp |  7 ++++--
 2 files changed, 18 insertions(+), 51 deletions(-)

diff --git a/dsp/fn529fe0.cpp b/dsp/fn529fe0.cpp
index 38ce3e7..c13329d 100644
--- a/dsp/fn529fe0.cpp
+++ b/dsp/fn529fe0.cpp
@@ -1,6 +1,8 @@
 #include "fn529fe0.hpp"
 #include "rt_div_tables.hpp"
 #include "rt_mask_tables.hpp"
+#include "fft.hpp"
+#include "fft_plan.hpp"
 #include <cmath>
 #include <algorithm>
 #include <cstring>
@@ -205,7 +207,7 @@ static inline void iir4_bidir_340510(float* x, size_t nbin) {
     acc = 0.0;
     for (size_t i = nbin; i-- > 0;) { double y = A2[i]*acc + B2[i]*x[i]; acc = y; x[i] = static_cast<float>(y); }
 }
-static inline void fir_min_phase_52b3cd(float* scr, size_t nbin) {
+static inline void fir_min_phase_52b3cd_internal(float* scr, size_t nbin) {
     // BLOCKMAP:52b3cd FIR min-phase 2049→4096 inv-RFFT fold×2 fwd EXP 1803831c0 q0.80
     // Real RFFT pipeline validated cascade_sim.py fir_kernel 0.0065dB. Gate RT_FIR=1
     // to keep canon 0.341 default. When enabled, scr (log domain) gets log|F| added.
@@ -214,68 +216,26 @@ static inline void fir_min_phase_52b3cd(float* scr, size_t nbin) {
     if (!fir_on) return;
     const size_t N = 4096;
     const double q = 0.80;
-    // Use fft:: RFFT (th2180/th1a90) — scale 2^-12 on inv already matches numpy 1/N
-    // Build plans (log2N=12)
-    extern void fft_init_plan_stub(); // dummy to force link
-    // fallback: naive DFT for now (N=4096, ~16M complex mults per call — okay for structural chain ~62 frames)
-    // periodic Hann
+    FFTPlan plan; fft::init_plan(&plan, 12);
     double hann[N];
     for (size_t i=0;i<N;i++) hann[i]=0.5*(1.0 - std::cos(2.0*M_PI*double(i)/double(N)));
-    // h = scr (complex)
     std::vector<std::complex<double>> h(N/2+1);
     for (size_t i=0;i<nbin;i++) h[i]=std::complex<double>(scr[i],0.0);
     h[N/2]=std::complex<double>(0.0,0.0);
-    // y = irfft(h)
     std::vector<double> y(N,0.0);
-    // naive irfft: y[n]= 1/N * sum_{k} H[k] e^{j2pi kn/N} + conj
-    for (size_t n=0;n<N;n++) {
-        std::complex<double> sum(0,0);
-        for (size_t k=0;k<=N/2;k++) {
-            double angle = 2.0*M_PI*double(k)*double(n)/double(N);
-            std::complex<double> tw(std::cos(angle), std::sin(angle));
-            if (k==0 || k==N/2) sum += h[k]*tw;
-            else sum += h[k]*tw + std::conj(h[k])*std::complex<double>(std::cos(-angle), std::sin(-angle));
-        }
-        y[n]= sum.real() / double(N);
-    }
+    fft::execute_real_inverse(&plan, h.data(), y.data());
     for (size_t i=1;i<N/2;i++) y[i]*=2.0;
     for (size_t i=N/2+1;i<N;i++) y[i]=0.0;
-    // X = rfft(y)
     std::vector<std::complex<double>> X(N/2+1);
-    for (size_t k=0;k<=N/2;k++) {
-        std::complex<double> sum(0,0);
-        for (size_t n=0;n<N;n++) {
-            double angle = -2.0*M_PI*double(k)*double(n)/double(N);
-            sum += y[n]*std::complex<double>(std::cos(angle), std::sin(angle));
-        }
-        X[k]=sum;
-    }
+    fft::execute_real_forward(&plan, y.data(), X.data());
     for (auto &c: X) c *= q;
     for (auto &c: X) c = std::exp(c);
-    // w = irfft(X)
     std::vector<double> w(N,0.0);
-    for (size_t n=0;n<N;n++) {
-        std::complex<double> sum(0,0);
-        for (size_t k=0;k<=N/2;k++) {
-            double angle = 2.0*M_PI*double(k)*double(n)/double(N);
-            std::complex<double> tw(std::cos(angle), std::sin(angle));
-            if (k==0 || k==N/2) sum += X[k]*tw;
-            else sum += X[k]*tw + std::conj(X[k])*std::complex<double>(std::cos(-angle), std::sin(-angle));
-        }
-        w[n]= sum.real() / double(N);
-    }
+    fft::execute_real_inverse(&plan, X.data(), w.data());
     for (size_t i=0;i<N/2;i++) w[i]*= hann[N/2+i];
     for (size_t i=N/2;i<N;i++) w[i]=0.0;
-    // F = rfft(w)
     std::vector<std::complex<double>> F(N/2+1);
-    for (size_t k=0;k<=N/2;k++) {
-        std::complex<double> sum(0,0);
-        for (size_t n=0;n<N;n++) {
-            double angle = -2.0*M_PI*double(k)*double(n)/double(N);
-            sum += w[n]*std::complex<double>(std::cos(angle), std::sin(angle));
-        }
-        F[k]=sum;
-    }
+    fft::execute_real_forward(&plan, w.data(), F.data());
     for (size_t i=0;i<nbin;i++) {
         double mag = std::abs(F[i]);
         if (mag < 1e-30) mag = 1e-30;
@@ -323,7 +283,7 @@ void chain_9_19(float* bands, float* tmp6f8, float* accVec,
     for (size_t i = 0; i < nbin; i++) bands[i] = std::log(std::max(bands[i], 1e-30f));
     // 16b: IIR4×2 bidir log-domain base 0x340510 52af09 (BLOCKMAP:639)
     iir4_bidir_340510(bands, nbin);
-    fir_min_phase_52b3cd(bands, nbin);
+    fir_min_phase_52b3cd_internal(bands, nbin);
     // 17: EXP#2 + exp-variant 140a40/140b00
     for (size_t i = 0; i < nbin; i++) bands[i] = expf_180296c80(bands[i]);
 }
@@ -386,4 +346,8 @@ void dry_wet(float* mask, float fVar30, float wet, size_t nbin) {
     }
 }
 
+void fir_min_phase_52b3cd(float* scr, size_t nbin) {
+    fir_min_phase_52b3cd_internal(scr, nbin);
+}
+
 }  // namespace fn529fe0
diff --git a/dsp/fn529fe0.hpp b/dsp/fn529fe0.hpp
index a42ede6..22ec325 100644
--- a/dsp/fn529fe0.hpp
+++ b/dsp/fn529fe0.hpp
@@ -67,10 +67,13 @@ void cascade_detect(
     bool is_magnitude = false      // true = input_data is already |z|, skip Phase 1
 );
 
+// FIR min-phase 52b3cd 2049→4096 (BLOCKMAP:760) — exposed for VLAW path
+void fir_min_phase_52b3cd(float* scr, size_t nbin);
+
 // Main chain 9–19 (BLOCKMAP:620) — DIVIDE/FMA/EXP/FIR proxy (1c)
 void chain_9_19(float* bands, float* tmp6f8, float* accVec,
-                const float* warp, const float* att, const float* rel,
-                size_t nbin);
+                 const float* warp, const float* att, const float* rel,
+                 size_t nbin);
 
 // ---- Legacy structural chain functions --------------------------------------