Altivec optimized stereo resampler by Romain Dolbeau (made it working under Linux myself)

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@11850 b3059339-0415-0410-9bf9-f77b7e298cf2

liba52/resample.c

@@ -19,6 +19,10 @@ int (* a52_resample) (float * _f, int16_t * s16)=NULL;
 #include "resample_mmx.c"
 #endif
 
+#ifdef HAVE_ALTIVEC
+#include "resample_altivec.c"
+#endif
+
 void* a52_resample_init(uint32_t mm_accel,int flags,int chans){
 void* tmp;
 
@@ -32,7 +36,17 @@ void* tmp;
 	}
     }
 #endif
-
+#ifdef HAVE_ALTIVEC
+    if(mm_accel&MM_ACCEL_PPC_ALTIVEC){
+      tmp=a52_resample_altivec(flags,chans);
+      if(tmp){
+       if(a52_resample==NULL) fprintf(stderr, "Using AltiVec optimized resampler\n");
+       a52_resample=tmp;
+       return tmp;
+      }
+    }
+#endif
+    
     tmp=a52_resample_C(flags,chans);
     if(tmp){
 	if(a52_resample==NULL) fprintf(stderr, "No accelerated resampler found\n");

liba52/resample_altivec.c

@@ -0,0 +1,74 @@
+// this code is based on a52dec/libao/audio_out_oss.c
+// AltiVec support Copyright (c) 2004 Romain Dolbeau <romain@dolbeau.org>
+
+#ifndef SYS_DARWIN
+#include <altivec.h>
+#endif
+
+const vector signed int magic = {0x43c00000,0x43c00000,0x43c00000,0x43c00000};
+
+static inline vector signed short convert16_altivec(vector signed int v1, vector signed int v2)
+{
+  register vector signed short result;
+  v1 = vec_subs(v1, magic);
+  v2 = vec_subs(v2, magic);
+  result = vec_packs(v1, v2);
+
+  return result;
+}
+
+static int a52_resample_STEREO_to_2_altivec(float * _f, int16_t * s16){
+#if 0
+  int i;
+  int32_t * f = (int32_t *) _f;
+  for (i = 0; i < 256; i++) {
+    s16[2*i] = convert (f[i]);
+    s16[2*i+1] = convert (f[i+256]);
+  }
+  return 2*256;
+#else
+  int i = 0;
+  int32_t * f = (int32_t *) _f;
+  register vector signed int f0, f4, f256, f260;
+  register vector signed short reven, rodd, r0, r1;
+
+  for (i = 0; i < 256; i+= 8) {
+    f0 = vec_ld(0, f);
+    f4 = vec_ld(16, f);
+    
+    f256 = vec_ld(1024, f);
+    f260 = vec_ld(1040, f);
+
+    reven = convert16_altivec(f0, f4);
+    rodd = convert16_altivec(f256, f260);
+
+    r0 = vec_mergeh(reven, rodd);
+    r1 = vec_mergel(reven, rodd);
+    
+    vec_st(r0, 0, s16);
+    vec_st(r1, 16, s16);
+
+    f += 8;
+    s16 += 16;
+  }
+  return(2*256);
+#endif
+}
+
+static void* a52_resample_altivec(int flags, int ch){
+fprintf(stderr, "Checking for AltiVec resampler : 0x%08x, %d\n", flags, ch);
+
+  switch (flags) {
+  case A52_CHANNEL:
+  case A52_STEREO:
+  case A52_DOLBY:
+    if(ch==2) return a52_resample_STEREO_to_2_altivec;
+    break;
+
+  default:
+	fprintf(stderr, "Unsupported flags: 0x%08x (%d channels)\n", flags, ch);
+	break;
+  }
+  return NULL;
+}
+