Full precision synth_full and dct32. Replaced all multiplications with proper 64 bit EMAC multiplications, which yields improved sound.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6638 a1c6a512-1295-4272-9138-f99709370657

apps/codecs/libmad/Makefile

@@ -14,7 +14,8 @@ ifdef APPEXTRA
 INCLUDES += -I$(APPSDIR)/$(APPEXTRA)
 endif
 
-MADOPTS =  -DFPM_DEFAULT -DNDEBUG -O2
+# NOTE: FPM_ define has been moved to global.h
+MADOPTS = -DNDEBUG -O2
 CFLAGS = $(GCCOPTS) $(MADOPTS)\
 $(INCLUDES) $(TARGET) $(EXTRA_DEFINES) -DMEM=${MEMORYSIZE}
 

apps/codecs/libmad/fixed.h

@@ -420,6 +420,29 @@ mad_fixed_t mad_f_mul_inline(mad_fixed_t x, mad_fixed_t y)
 
 #  define MAD_F_SCALEBITS  MAD_F_FRACBITS
 
+# elif defined(FPM_COLDFIRE_EMAC)
+
+/* mad_f_mul using the Coldfire MCF5249 EMAC unit. Loses 3 bits of accuracy.
+   Note that we don't define any of the libmad accumulator macros, as
+   any functions that use these should have the relevant sections rewritten
+   in assembler to utilise the EMAC accumulators properly.
+   Assumes the default +/- 3.28 fixed point format 
+ */
+#define mad_f_mul(x, y) \
+({ \
+  mad_fixed64hi_t hi; \
+  asm volatile("mac.l %[a], %[b], %%acc0\n\t" \
+               "movclr.l %%acc0, %[hi]\n\t" \
+               "asl.l #3, %[hi]" \
+               : [hi] "=d" (hi) \
+               : [a] "r" ((x)), [b] "r" ((y))); \
+  hi; \
+})
+/* Define dummy mad_f_scale64 to prevent libmad from defining MAD_F_SCALEBITS
+   below. Having MAD_F_SCALEBITS defined screws up the PRESHIFT macro in synth.h
+ */
+#define mad_f_scale64(hi, lo) (lo)
+
 /* --- Default ------------------------------------------------------------- */
 
 # elif defined(FPM_DEFAULT)

apps/codecs/libmad/global.h

@@ -24,6 +24,12 @@
 # ifndef LIBMAD_GLOBAL_H
 # define LIBMAD_GLOBAL_H
 
+#if CONFIG_CPU==MCF5249 && !defined(SIMULATOR)
+#define FPM_COLDFIRE_EMAC
+#else
+#define FPM_DEFAULT
+#endif
+
 /* conditional debugging */
 
 # if defined(DEBUG) && defined(NDEBUG)

apps/codecs/libmad/synth.c

@@ -102,7 +102,21 @@ void mad_synth_mute(struct mad_synth *synth)
 
 /* possible DCT speed optimization */
 
-# if defined(OPT_SPEED) && defined(MAD_F_MLX)
+/* This is a Coldfire version of the OPT_SPEED optimisation below, but in the
+   case of Coldfire it doesn't lose any more precision than we would ordinarily
+   lose, */
+# ifdef FPM_COLDFIRE_EMAC
+#  define OPT_DCTO
+#  define MUL(x, y) \
+    ({ \
+       mad_fixed64hi_t hi; \
+       asm volatile("mac.l %[a], %[b], %%acc0\n\t" \
+                    "movclr.l %%acc0, %[hi]" \
+                    : [hi] "=r" (hi) \
+                    : [a] "r" ((x)), [b] "r" ((y))); \
+       hi; \
+     })
+# elif defined(OPT_SPEED) && defined(MAD_F_MLX)
 #  define OPT_DCTO
 #  define MUL(x, y)  \
     ({ mad_fixed64hi_t hi;  \
@@ -555,8 +569,8 @@ void synth_full(struct mad_synth *, struct mad_frame const *,
  * DESCRIPTION:	perform full frequency PCM synthesis
  */
 
-/* optimised version of synth full, requires OPT_SSO at the moment */
+/* optimised version of synth_full */
-# if CONFIG_CPU==MCF5249 && defined(OPT_SSO) && !defined(SIMULATOR)
+# ifdef FPM_COLDFIRE_EMAC 
 static
 void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
 		unsigned int nch, unsigned int ns)
@@ -566,10 +580,9 @@ void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
   mad_fixed_t const (*sbsample)[36][32];
   mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
   mad_fixed_t const (*Dptr)[32];
-  mad_fixed64hi_t hi = 0;
+  mad_fixed64hi_t hi;
-  mad_fixed64lo_t lo;
 
-  asm volatile("move.l #0, %macsr"); /* need integer mode */
+  asm volatile("move.l #0x20, %macsr"); /* fractional mode */
   
   for (ch = 0; ch < nch; ++ch) {
     sbsample = &frame->sbsample[ch];
@@ -613,10 +626,12 @@ void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
         "mac.l %%d5, %%a5, 16(%4), %%a5, %%acc0\n\t"
         "mac.l %%d6, %%a5, 8(%4), %%a5, %%acc0\n\t"
         "mac.l %%d7, %%a5, %%acc0\n\t"
-        "movclr.l %%acc0, %0"
+        "movclr.l %%acc0, %0\n\t"
-        : "=ad" (lo) : "a" (*fx), "a" (*Dptr + po), "a" (*fe), "a" (*Dptr + pe) : "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "a5");
+        : "=r" (hi) 
+        : "a" (*fx), "a" (*Dptr + po), "a" (*fe), "a" (*Dptr + pe) 
+        : "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "a5");
 
-      *pcm1++ = SHIFT(MLZ(hi, lo));
+      *pcm1++ = hi << 3; /* shift result to libmad's fixed point format */
 
       pcm2 = pcm1 + 30;
 
@@ -646,12 +661,12 @@ void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
           "mac.l %%d2, %%a5, 56(%4), %%a5, %%acc0\n\t"
           "mac.l %%d1, %%a5, (%4), %%a5, %%acc0\n\t"
           "mac.l %%d0, %%a5, %%acc0\n\t"
-          "movclr.l %%acc0, %0"
+          "movclr.l %%acc0, %0\n\t"
-          : "=ad" (lo) 
+          : "=r" (hi) 
           : "a" (*fo), "a" (*Dptr + po), "a" (*fe), "a" (*Dptr + pe) 
           : "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "a5");
 
-	*pcm1++ = SHIFT(MLZ(hi, lo));
+	*pcm1++ = hi << 3;
         
         asm volatile(
           "movem.l (%1), %%d0-%%d7\n\t"
@@ -674,12 +689,12 @@ void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
           "mac.l %%d2, %%a5, 68(%4), %%a5, %%acc0\n\t"
           "mac.l %%d1, %%a5, 60(%4), %%a5, %%acc0\n\t"
           "mac.l %%d0, %%a5, %%acc0\n\t"
-          "movclr.l %%acc0, %0"
+          "movclr.l %%acc0, %0\n\t"
-          : "=ad" (lo) 
+          : "=r" (hi) 
           : "a" (*fe), "a" (*Dptr - pe), "a" (*fo), "a" (*Dptr - po) 
           : "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "a5");
 
-	*pcm2-- = SHIFT(MLZ(hi, lo));
+	*pcm2-- = hi << 3;
 
 	++fo;
       }
@@ -696,11 +711,11 @@ void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
         "mac.l %%d5, %%a5, 16(%2), %%a5, %%acc0\n\t"
         "mac.l %%d6, %%a5, 8(%2), %%a5, %%acc0\n\t"
         "mac.l %%d7, %%a5, %%acc0\n\t"
-        "movclr.l %%acc0, %0" 
+        "movclr.l %%acc0, %0\n\t"
-        : "=ad" (lo) : "a" (*fo), "a" (*Dptr + po) 
+        : "=r" (hi) : "a" (*fo), "a" (*Dptr + po) 
         : "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "a5");
 
-      *pcm1 = SHIFT(-MLZ(hi, lo));
+      *pcm1 = -(hi << 3);
       pcm1 += 16;
 
       phase = (phase + 1) % 16;