git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@14524 27425a3e-05d8-49a3-a47f-9c15f0e5edd8

test/corebmk/source/test/ffbench_mod.c

@@ -0,0 +1,89 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+/*
+    This module is based on the work of John Walker (April of 1989) and
+    merely adapted to work in ChibiOS. The author has not specified
+    additional license terms so this is released using the most permissive
+    license used in ChibiOS. The license covers the changes only, not the
+    original work.
+ */
+
+static void corebmk_fourn(Float data[], int nn[], const int ndim, const int isign) {
+  int i1, i2, i3;
+  int i2rev, i3rev, ip1, ip2, ip3, ifp1, ifp2;
+  int ibit, idim, k1, k2, n, nprev, nrem, ntot;
+  Float tempi, tempr;
+  double theta, wi, wpi, wpr, wr, wtemp;
+
+  ntot = 1;
+  for (idim = 1; idim <= ndim; idim++) {
+    ntot *= nn[idim];
+  }
+  nprev = 1;
+  for (idim = ndim; idim >= 1; idim--) {
+    n = nn[idim];
+    nrem = ntot / (n * nprev);
+    ip1 = nprev << 1;
+    ip2 = ip1 * n;
+    ip3 = ip2 * nrem;
+    i2rev = 1;
+    for (i2 = 1; i2 <= ip2; i2 += ip1) {
+      if (i2 < i2rev) {
+        for (i1 = i2; i1 <= i2 + ip1 - 2; i1 += 2) {
+          for (i3 = i1; i3 <= ip3; i3 += ip2) {
+            i3rev = i2rev + i3 - i2;
+            SWAP(data[i3], data[i3rev]);
+            SWAP(data[i3 + 1], data[i3rev + 1]);
+          }
+        }
+      }
+      ibit = ip2 >> 1;
+      while (ibit >= ip1 && i2rev > ibit) {
+        i2rev -= ibit;
+        ibit >>= 1;
+      }
+      i2rev += ibit;
+    }
+    ifp1 = ip1;
+    while (ifp1 < ip2) {
+      ifp2 = ifp1 << 1;
+      theta = isign * 6.28318530717959 / (ifp2 / ip1);
+      wtemp = sin(0.5 * theta);
+      wpr = -2.0 * wtemp * wtemp;
+      wpi = sin(theta);
+      wr = 1.0;
+      wi = 0.0;
+      for (i3 = 1; i3 <= ifp1; i3 += ip1) {
+        for (i1 = i3; i1 <= i3 + ip1 - 2; i1 += 2) {
+          for (i2 = i1; i2 <= ip3; i2 += ifp2) {
+            k1 = i2;
+            k2 = k1 + ifp1;
+            tempr = wr * data[k2] - wi * data[k2 + 1];
+            tempi = wr * data[k2 + 1] + wi * data[k2];
+            data[k2] = data[k1] - tempr;
+            data[k2 + 1] = data[k1 + 1] - tempi;
+            data[k1] += tempr;
+            data[k1 + 1] += tempi;
+          }
+        }
+        wr = (wtemp = wr) * wpr - wi * wpi + wr;
+        wi = wi * wpr + wtemp * wpi + wi;
+      }
+      ifp1 = ifp2;
+    }
+    nprev *= n;
+  }
+}