ch18

[book_gpu.git] / BookGPU / Chapters / chapter4 / code / convoSepShH.cu~

diff --git a/BookGPU/Chapters/chapter4/code/convoSepShH.cu~ b/BookGPU/Chapters/chapter4/code/convoSepShH.cu~
index 8f3e73d5eed79c625b9ecae5efe1b59524010aa5..19f533e1cf09d5f40c4aa847ad509dfb935c6852 100644 (file)
--- a/BookGPU/Chapters/chapter4/code/convoSepShH.cu~
+++ b/BookGPU/Chapters/chapter4/code/convoSepShH.cu~
@@ -2,28 +2,28 @@ __global__ void kernel_convoSepShx8pH(unsigned char *output, int j_dim, int r)
 {
   int ic, jc, p;
   int k = 2*r+1 ;
-  float outval0=0.0, outval1=0.0, outval2=0.0, outval3=0.0, outval4=0.0, outval5=0.0, outval6=0.0, outval7=0.0 ;
-  int bdimX = blockDim.x<<3 ;
-  int tidX = threadIdx.x<<3 ;
+  float outval0=0.0, outval1=0.0, outval2=0.0, outval3=0.0 ;
+  float outval4=0.0, outval5=0.0, outval6=0.0, outval7=0.0 ;
+  int bdimX = blockDim.x<<3 ; // all packets width
+  int tidX = threadIdx.x<<3 ; // one packet offset 
     
-  // coordonnees absolues du point de base
+  // absolute coordinates of one packet base point
   int j = (__umul24(blockIdx.x,blockDim.x) + threadIdx.x)<<3 ; 
   int i = __umul24( blockIdx.y, blockDim.y) + threadIdx.y ;
-  int j0= __umul24(blockIdx.x,blockDim.x)<<3 ;  
-  int idx = __umul24(i,j_dim) + j ;              // indice  dans l'image
+  int j0= __umul24(blockIdx.x,blockDim.x)<<3 ;
+  // absolute index in the image
+  int idx = __umul24(i,j_dim) + j ;
 
-  
-  // chargement en smem
+  // offset of one ROI row in shared memory
   int idrow = threadIdx.y*(bdimX+k-1) ;
   
   extern __shared__ unsigned char roi8p[];
 
-  // bloc 0 (a gauche)
+  // top left block
   for (p=0; p<8; p++)
        roi8p[  idrow  + tidX +p ] = tex2D(tex_img_inc, j-r+p  , i) ;
-
-  // a droite
-  if ( threadIdx.x < r ) //...ou plutot ce qu'il en manque
+  // top right block
+  if ( threadIdx.x < r )
        {
          roi8p[  idrow + bdimX + threadIdx.x    ] = tex2D( tex_img_inc, j0-r +bdimX+threadIdx.x  , i ) ;
          roi8p[  idrow + bdimX + threadIdx.x +r ] = tex2D( tex_img_inc, j0   +bdimX+threadIdx.x  , i ) ;
@@ -31,8 +31,7 @@ __global__ void kernel_convoSepShx8pH(unsigned char *output, int j_dim, int r)
   
   __syncthreads();
   
-  // calculs de convolution
-  // passe horizontale
+  // horizontal convolution
   for (jc=0 ; jc<k ; jc++)
          {
                int baseRoi = idrow + tidX +jc ;
@@ -47,13 +46,13 @@ __global__ void kernel_convoSepShx8pH(unsigned char *output, int j_dim, int r)
                outval7 += valMask*roi8p[  baseRoi +7 ] ;
          }
        
-  // 1 pixel par thread --> global mem
-  output[ idx   ] = outval0 ;
-  output[ idx+1 ] = outval1 ;
-  output[ idx+2 ] = outval2 ;
-  output[ idx+3 ] = outval3 ;
-  output[ idx+4 ] = outval4 ;
-  output[ idx+5 ] = outval5 ;
-  output[ idx+6 ] = outval6 ;
-  output[ idx+7 ] = outval7 ;
+  // 8 pixels per thread --> global mem
+  output[ idx++ ] = outval0 ;
+  output[ idx++ ] = outval1 ;
+  output[ idx++ ] = outval2 ;
+  output[ idx++ ] = outval3 ;
+  output[ idx++ ] = outval4 ;
+  output[ idx++ ] = outval5 ;
+  output[ idx++ ] = outval6 ;
+  output[ idx++ ] = outval7 ;
 }