Unrolled version of the pitch correlation
About 30% faster on x86.
diff --git a/celt/pitch.c b/celt/pitch.c
index 26f9617..7213606 100644
--- a/celt/pitch.c
+++ b/celt/pitch.c
@@ -169,6 +169,106 @@
}
+#if 0 /* This is a simple version of the pitch correlation that should work
+ well on DSPs like Blackfin and TI C5x/C6x */
+
+static void pitch_xcorr(opus_val16 *x, opus_val16 *y, opus_val32 *xcorr, int len, int max_pitch
+#ifdef FIXED_POINT
+ ,opus_val32 *maxval
+#endif
+ )
+{
+ int i, j;
+#ifdef FIXED_POINT
+ opus_val32 maxcorr=-1;
+#endif
+ for (i=0;i<max_pitch;i++)
+ {
+ opus_val32 sum = 0;
+ for (j=0;j<len;j++)
+ sum = MAC16_16(sum, x[j],y[i+j]);
+ xcorr[i] = MAX32(-1, sum);
+#ifdef FIXED_POINT
+ maxcorr = MAX32(maxcorr, sum);
+#endif
+ }
+#ifdef FIXED_POINT
+ *maxval = maxcorr;
+#endif
+}
+
+#else /* Unrolled version of the pitch correlation -- runs faster on x86 and ARM */
+
+static void pitch_xcorr(opus_val16 *_x, opus_val16 *_y, opus_val32 *xcorr, int len, int max_pitch
+#ifdef FIXED_POINT
+ ,opus_val32 *maxval
+#endif
+ )
+{
+ int i,j;
+#ifdef FIXED_POINT
+ opus_val32 maxcorr=-1;
+#endif
+ for (i=0;i<max_pitch;i+=4)
+ {
+ /* Compute correlation*/
+ /*corr[nb_pitch-1-i]=inner_prod(x, _y+i, len);*/
+ opus_val32 sum1=0;
+ opus_val32 sum2=0;
+ opus_val32 sum3=0;
+ opus_val32 sum4=0;
+ const opus_val16 *y = _y+i;
+ const opus_val16 *x = _x;
+ opus_val16 y0, y1, y2, y3;
+ /*y0=y[0];y1=y[1];y2=y[2];y3=y[3];*/
+ y0=*y++;
+ y1=*y++;
+ y2=*y++;
+ for (j=0;j<len;j+=4)
+ {
+ opus_val16 tmp;
+ tmp = *x++;
+ y3=*y++;
+ sum1 = MAC16_16(sum1,tmp,y0);
+ sum2 = MAC16_16(sum2,tmp,y1);
+ sum3 = MAC16_16(sum3,tmp,y2);
+ sum4 = MAC16_16(sum4,tmp,y3);
+ tmp=*x++;
+ y0=*y++;
+ sum1 = MAC16_16(sum1,tmp,y1);
+ sum2 = MAC16_16(sum2,tmp,y2);
+ sum3 = MAC16_16(sum3,tmp,y3);
+ sum4 = MAC16_16(sum4,tmp,y0);
+ tmp=*x++;
+ y1=*y++;
+ sum1 = MAC16_16(sum1,tmp,y2);
+ sum2 = MAC16_16(sum2,tmp,y3);
+ sum3 = MAC16_16(sum3,tmp,y0);
+ sum4 = MAC16_16(sum4,tmp,y1);
+ tmp=*x++;
+ y2=*y++;
+ sum1 = MAC16_16(sum1,tmp,y3);
+ sum2 = MAC16_16(sum2,tmp,y0);
+ sum3 = MAC16_16(sum3,tmp,y1);
+ sum4 = MAC16_16(sum4,tmp,y2);
+ }
+ xcorr[i]=MAX32(-1, sum1);
+ xcorr[i+1]=MAX32(-1, sum2);
+ xcorr[i+2]=MAX32(-1, sum3);
+ xcorr[i+3]=MAX32(-1, sum4);
+#ifdef FIXED_POINT
+ sum1 = MAX32(sum1, sum2);
+ sum3 = MAX32(sum3, sum4);
+ sum1 = MAX32(sum1, sum3);
+ maxcorr = MAX32(maxcorr, sum1);
+#endif
+ }
+#ifdef FIXED_POINT
+ *maxval = maxcorr;
+#endif
+}
+
+#endif
void pitch_search(const opus_val16 * OPUS_RESTRICT x_lp, opus_val16 * OPUS_RESTRICT y,
int len, int max_pitch, int *pitch)
{
@@ -179,7 +279,7 @@
VARDECL(opus_val16, y_lp4);
VARDECL(opus_val32, xcorr);
#ifdef FIXED_POINT
- opus_val32 maxcorr=1;
+ opus_val32 maxcorr;
opus_val32 xmax, ymax;
int shift=0;
#endif
@@ -220,16 +320,12 @@
/* Coarse search with 4x decimation */
- for (i=0;i<max_pitch>>2;i++)
- {
- opus_val32 sum = 0;
- for (j=0;j<len>>2;j++)
- sum = MAC16_16(sum, x_lp4[j],y_lp4[i+j]);
- xcorr[i] = MAX32(-1, sum);
+ pitch_xcorr(x_lp4, y_lp4, xcorr, len>>2, max_pitch>>2
#ifdef FIXED_POINT
- maxcorr = MAX32(maxcorr, sum);
+ ,&maxcorr
#endif
- }
+ );
+
find_best_pitch(xcorr, y_lp4, len>>2, max_pitch>>2, best_pitch
#ifdef FIXED_POINT
, 0, maxcorr