From 531cf591e6c086ec0074e5630ce2c2db0e84bd3e Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Sat, 25 May 2013 07:41:55 -0400
Subject: [PATCH] Speeds up celt_iir() by more than a factor of two.
Again, this only impacts the PLC and we assume the order is a multiple of 4.
---
celt/celt_lpc.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 92 insertions(+), 4 deletions(-)
diff --git a/celt/celt_lpc.c b/celt/celt_lpc.c
index 898312147..d344618a8 100644
--- a/celt/celt_lpc.c
+++ b/celt/celt_lpc.c
@@ -178,17 +178,18 @@ void celt_fir(const opus_val16 *_x,
#endif
}
-void celt_iir(const opus_val32 *x,
+void celt_iir(const opus_val32 *_x,
const opus_val16 *den,
- opus_val32 *y,
+ opus_val32 *_y,
int N,
int ord,
opus_val16 *mem)
{
+#ifdef SMALL_FOOTPRINT
int i,j;
for (i=0;i<N;i++)
{
- opus_val32 sum = x[i];
+ opus_val32 sum = _x[i];
for (j=0;j<ord;j++)
{
sum -= MULT16_16(den[j],mem[j]);
@@ -198,8 +199,95 @@ void celt_iir(const opus_val32 *x,
mem[j]=mem[j-1];
}
mem[0] = ROUND16(sum,SIG_SHIFT);
- y[i] = sum;
+ _y[i] = sum;
+ }
+#else
+ int i,j;
+ VARDECL(opus_val16, rden);
+ VARDECL(opus_val16, y);
+ SAVE_STACK;
+
+ celt_assert((ord&3)==0);
+ ALLOC(rden, ord, opus_val16);
+ ALLOC(y, N+ord, opus_val16);
+ for(i=0;i<ord;i++)
+ rden[i] = den[ord-i-1];
+ for(i=0;i<ord;i++)
+ y[i] = -mem[ord-i-1];
+ for(;i<N+ord;i++)
+ y[i]=0;
+ for (i=0;i<N-3;i+=4)
+ {
+ opus_val32 sum1=0;
+ opus_val32 sum2=0;
+ opus_val32 sum3=0;
+ opus_val32 sum4=0;
+ const opus_val16 *yy = y+i;
+ const opus_val16 *z = rden;
+ opus_val16 y_0, y_1, y_2, y_3;
+ sum1 = _x[i ];
+ sum2 = _x[i+1];
+ sum3 = _x[i+2];
+ sum4 = _x[i+3];
+ y_3=0; /* gcc doesn't realize that y_3 can't be used uninitialized */
+ y_0=*yy++;
+ y_1=*yy++;
+ y_2=*yy++;
+ for (j=0;j<ord-3;j+=4)
+ {
+ opus_val16 tmp;
+ tmp = *z++;
+ y_3=*yy++;
+ sum1 = MAC16_16(sum1,tmp,y_0);
+ sum2 = MAC16_16(sum2,tmp,y_1);
+ sum3 = MAC16_16(sum3,tmp,y_2);
+ sum4 = MAC16_16(sum4,tmp,y_3);
+ tmp=*z++;
+ y_0=*yy++;
+ sum1 = MAC16_16(sum1,tmp,y_1);
+ sum2 = MAC16_16(sum2,tmp,y_2);
+ sum3 = MAC16_16(sum3,tmp,y_3);
+ sum4 = MAC16_16(sum4,tmp,y_0);
+ tmp=*z++;
+ y_1=*yy++;
+ sum1 = MAC16_16(sum1,tmp,y_2);
+ sum2 = MAC16_16(sum2,tmp,y_3);
+ sum3 = MAC16_16(sum3,tmp,y_0);
+ sum4 = MAC16_16(sum4,tmp,y_1);
+ tmp=*z++;
+ y_2=*yy++;
+ sum1 = MAC16_16(sum1,tmp,y_3);
+ sum2 = MAC16_16(sum2,tmp,y_0);
+ sum3 = MAC16_16(sum3,tmp,y_1);
+ sum4 = MAC16_16(sum4,tmp,y_2);
+ }
+ y[i+ord ] = -ROUND16(sum1,SIG_SHIFT);
+ _y[i ] = sum1;
+ sum2 = MAC16_16(sum2, y[i+ord ], den[0]);
+ y[i+ord+1] = -ROUND16(sum2,SIG_SHIFT);
+ _y[i+1] = sum2;
+ sum3 = MAC16_16(sum3, y[i+ord+1], den[0]);
+ sum3 = MAC16_16(sum3, y[i+ord ], den[1]);
+ y[i+ord+2] = -ROUND16(sum3,SIG_SHIFT);
+ _y[i+2] = sum3;
+
+ sum4 = MAC16_16(sum4, y[i+ord+2], den[0]);
+ sum4 = MAC16_16(sum4, y[i+ord+1], den[1]);
+ sum4 = MAC16_16(sum4, y[i+ord ], den[2]);
+ y[i+ord+3] = -ROUND16(sum4,SIG_SHIFT);
+ _y[i+3] = sum4;
}
+ for (;i<N;i++)
+ {
+ opus_val32 sum = _x[i];
+ for (j=0;j<ord;j++)
+ sum -= MULT16_16(rden[j],y[i+j]);
+ y[i+ord] = ROUND16(sum,SIG_SHIFT);
+ _y[i] = sum;
+ }
+ for(i=0;i<ord;i++)
+ mem[i] = _y[N-i-1];
+#endif
}
void _celt_autocorr(
--
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