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, 46 insertions, 0 deletions

diff --git a/apps/codecs/libwmapro/wmapro_math.h b/apps/codecs/libwmapro/wmapro_math.h
new file mode 100644
index 0000000..83fbb40
--- /dev/null
+++ b/apps/codecs/libwmapro/wmapro_math.h
@@ -0,0 +1,46 @@
+#include <inttypes.h>
+#include "types.h"
+
+#define fixtof16(x)       (float)((float)(x) / (float)(1 << 16))
+#define ftofix16(x)       ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5:0.5)))
+
+static inline FIXED fixmulshift(FIXED x, FIXED y, int shamt)
+{
+    int64_t temp;
+    temp = x;
+    temp *= y;
+
+    temp >>= shamt;
+
+    return (int32_t)temp;
+}
+
+
+static inline void vector_fixmul_window(FIXED *dst, const FIXED *src0, 
+                                   const FIXED *src1, const FIXED *win, 
+                                   FIXED add_bias, int len)
+{
+    int i, j;
+    dst += len;
+    win += len;
+    src0+= len;
+        for(i=-len, j=len-1; i<0; i++, j--) {
+        FIXED s0 = src0[i];
+        FIXED s1 = src1[j];
+        FIXED wi = win[i];
+        FIXED wj = win[j];
+        dst[i] = fixmulshift(s0,-1*wj,31) - fixmulshift(s1,-1*wi,31) + (add_bias<<16);
+        dst[j] = fixmulshift(s0,-1*wi,31) + fixmulshift(s1,-1*wj,31) + (add_bias<<16);
+    }   
+    
+}
+
+static inline void vector_fixmul_scalar(FIXED *dst, const FIXED *src, FIXED mul,
+                                        int len)
+{
+    int i;
+    for(i=0; i<len; i++) {
+        dst[i] = fixmulshift(src[i],mul,32);
+    }   
+    
+}