shithub: opus

Info  •  Files  •  Log  •  Branches

Further speedup in cwrsi() by using the special case for n=2

--- a/celt/cwrs.c

+++ b/celt/cwrs.c

@@ -461,12 +461,12 @@

 }

 static void cwrsi(int _n,int _k,opus_uint32 _i,int *_y){

-  int s;

+  opus_uint32 p;

+  int         s;

+  int         k0;

   celt_assert(_k>0);

   celt_assert(_n>1);

-  do{

-    opus_uint32 p;

-    int         k0;

+  while(_n>2){

     /*Are the pulses in this dimension negative?*/

     p=CELT_PVQ_U(_n,_k+1);

     s=-(_i>=p);

@@ -495,9 +495,18 @@

     for(;p>_i;p=CELT_PVQ_U_ROW[_k][_n])_k--;

     _i-=p;

     *_y++=(k0-_k+s)^s;

+    _n--;

   }

-  while(--_n>1);

-  s=-(_i>=1);

+  /*_n==2*/

+  p=2*_k+1;

+  s=-(_i>=p);

+  _i-=p&s;

+  k0=_k;

+  _k=(_i+1)>>1;

+  if(_k)_i-=2*_k-1;

+  *_y++=(k0-_k+s)^s;

+  /*_n==1*/

+  s=-_i;

   *_y=(_k+s)^s;

 }