move (i)MDCT and FFT code to separate files

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14776 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 152 insertions, 0 deletions

diff --git a/apps/codecs/libwma/fft.c b/apps/codecs/libwma/fft.c
new file mode 100644
index 0000000000..3def74d92c
--- /dev/null
+++ b/apps/codecs/libwma/fft.c
@@ -0,0 +1,152 @@
+/*
+ * WMA compatible decoder
+ * Copyright (c) 2002 The FFmpeg Project.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "wmadec.h"
+#include "wmafixed.h"
+
+FFTComplex  exptab0[512] IBSS_ATTR;
+
+/* butter fly op */
+#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
+{\
+  fixed32 ax, ay, bx, by;\
+  bx=pre1;\
+  by=pim1;\
+  ax=qre1;\
+  ay=qim1;\
+  pre = (bx + ax);\
+  pim = (by + ay);\
+  qre = (bx - ax);\
+  qim = (by - ay);\
+}
+
+
+int fft_calc_unscaled(FFTContext *s, FFTComplex *z)
+{
+    int ln = s->nbits;
+    int j, np, np2;
+    int nblocks, nloops;
+    register FFTComplex *p, *q;
+   // FFTComplex *exptab = s->exptab;
+    int l;
+    fixed32 tmp_re, tmp_im;
+    int tabshift = 10-ln;
+
+    np = 1 << ln;
+
+
+    /* pass 0 */
+
+    p=&z[0];
+    j=(np >> 1);
+    do
+    {
+        BF(p[0].re, p[0].im, p[1].re, p[1].im,
+           p[0].re, p[0].im, p[1].re, p[1].im);
+        p+=2;
+    }
+    while (--j != 0);
+
+    /* pass 1 */
+
+
+    p=&z[0];
+    j=np >> 2;
+    if (s->inverse)
+    {
+        do
+        {
+            BF(p[0].re, p[0].im, p[2].re, p[2].im,
+               p[0].re, p[0].im, p[2].re, p[2].im);
+            BF(p[1].re, p[1].im, p[3].re, p[3].im,
+               p[1].re, p[1].im, -p[3].im, p[3].re);
+            p+=4;
+        }
+        while (--j != 0);
+    }
+    else
+    {
+        do
+        {
+            BF(p[0].re, p[0].im, p[2].re, p[2].im,
+               p[0].re, p[0].im, p[2].re, p[2].im);
+            BF(p[1].re, p[1].im, p[3].re, p[3].im,
+               p[1].re, p[1].im, p[3].im, -p[3].re);
+            p+=4;
+        }
+        while (--j != 0);
+    }
+    /* pass 2 .. ln-1 */
+
+    nblocks = np >> 3;
+    nloops = 1 << 2;
+    np2 = np >> 1;
+    do
+    {
+        p = z;
+        q = z + nloops;
+        for (j = 0; j < nblocks; ++j)
+        {
+            BF(p->re, p->im, q->re, q->im,
+               p->re, p->im, q->re, q->im);
+
+            p++;
+            q++;
+            for(l = nblocks; l < np2; l += nblocks)
+            {
+                CMUL(&tmp_re, &tmp_im, exptab0[(l<<tabshift)].re, exptab0[(l<<tabshift)].im, q->re, q->im);
+                //CMUL(&tmp_re, &tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
+                BF(p->re, p->im, q->re, q->im,
+                   p->re, p->im, tmp_re, tmp_im);
+                p++;
+                q++;
+            }
+
+            p += nloops;
+            q += nloops;
+        }
+        nblocks = nblocks >> 1;
+        nloops = nloops << 1;
+    }
+    while (nblocks != 0);
+    return 0;
+}
+
+int fft_init_global()
+{
+    int i, n;
+    fixed32 c1, s1, s2;
+
+    n=1<<10;
+    s2 = 1 ? 1 : -1;
+    for(i=0;i<(n/2);++i)
+    {
+        fixed32 ifix = itofix32(i);
+        fixed32 nfix = itofix32(n);
+        fixed32 res = fixdiv32(ifix,nfix);
+
+        s1 = fsincos(res<<16, &c1);
+
+        exptab0[i].re = c1;
+        exptab0[i].im = s1*s2;
+    }
+
+    return 0;
+}
+