Partial conversion of the wmapro decoder to fixed point arithmetic. Currently inverse quantization & rescaling,

imdct and windowing are all in fixed point.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27302 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 51 insertions, 0 deletions

diff --git a/apps/codecs/libwmapro/wmapro_mdct.c b/apps/codecs/libwmapro/wmapro_mdct.c
new file mode 100644
index 0000000..12cd8ce
--- /dev/null
+++ b/apps/codecs/libwmapro/wmapro_mdct.c
@@ -0,0 +1,51 @@
+#include <inttypes.h>
+#include "wmapro_mdct.h"
+#include "mdct_tables.h"    /* for sincos_lookup_wmap */
+#include "../lib/mdct_lookup.h" /* for revtab */
+#include "../lib/fft.h"     /* for FFT data structures */
+#include "codeclib.h"
+#include "../lib/codeclib_misc.h" /* for XNPROD31 */
+
+void imdct_half(unsigned int nbits, int32_t *output, const int32_t *input){
+    int k, n8, n4, n2, n, j;
+    //const uint16_t *revtab = s->revtab;
+    const int32_t *in1, *in2;
+    FFTComplex *z = (FFTComplex *)output;
+
+    n = 1 << nbits;
+    n2 = n >> 1;
+    n4 = n >> 2;
+    n8 = n >> 3;
+    
+    const int32_t *T = sincos_lookup_wmap + ((n2) - (1<<7));
+
+    /* pre rotation */
+    const int revtab_shift = (14- nbits);
+    in1 = input;
+    in2 = input + n2 - 1;
+    int step = 2<<(12-nbits);
+    for(k = 0; k < n4; k++) {
+        j=revtab[k]>>revtab_shift;
+        XNPROD31(*in2, *in1, T[1]<<16, T[0]<<16, &z[j].re, &z[j].im );
+        in1 += 2;
+        in2 -= 2;
+        T += 2;
+    }
+
+    ff_fft_calc_c(nbits-2, z);
+
+    /* post rotation + reordering */
+    T = sincos_lookup_wmap + ((n2) - (1<<7)) + n4;
+    const int32_t *V = T;
+    for(k = 0; k < n8; k++) {
+        int32_t r0, i0, r1, i1;
+        XNPROD31(z[n8-k-1].im, z[n8-k-1].re, T[0]<<16, T[1]<<16, &r0, &i1 );
+        XNPROD31(z[n8+k  ].im, z[n8+k  ].re, V[0]<<16, V[1]<<16, &r1, &i0 );
+        z[n8-k-1].re = r0;
+        z[n8-k-1].im = i0;
+        z[n8+k  ].re = r1;
+        z[n8+k  ].im = i1;
+        T-=2;
+        V+=2;
+    }
+}