About the useage of DAT_copy

Hi, all

             I do some image processing in CCS 2.21 on evmDM642.I use the IMGLIB to process the video. I list the part of my code.I have two questions:

            for ( i = 0; i < numLines-2; i ++ )
             {              
                        IMG_median_3x3(capFrameBuf->frame.iFrm.y1+i*capLinePitch,720,nMemTemp_out+i*capLinePitch);
           
                       m_nID=DAT_copy(capFrameBuf->frame.iFrm.cb1+i*(capLinePitch>>1),nMemTemp_cb,numPixels>>1);
                       DAT_wait(m_nID);
                       m_nID=DAT_copy(capFrameBuf->frame.iFrm.cr1+i*(capLinePitch>>1),nMemTemp_cr,numPixels>>1);
                       DAT_wait(m_nID); 
                       ICETEKDM642PCIImagebinary();
                       m_nID=DAT_copy(nSegmentTemp,nMemTemp_out+i*capLinePitch,720);
                       DAT_wait(m_nID);
                       IMG_perimeter(nMemTemp_out+i*capLinePitch,720,binary_out+i*capLinePitch);

                      .......

           1: 

           I want to test the overhead of the function of the ICETEKDM642PCIImagebinary(), I write a clock function such as:

           clock_t start,stop,overhead;

           start=clock();    stop=clock();    overhead=stop-start;

           start=clock();

           ICETEKDM642PCIImagebinary();

           stop=clock()

           printf("%d \n",stop-start-overhead);

           But the result is 0.   Why?  I track the running step by step,the application turn into the function of the  ICETEKDM642PCIImagebinary() actually. Why?

           When I use the profile tool to test the cycles of this function,but it can't run continue. WHY?

           2:

            #pragma DATA_ALIGN(nMemTemp_out,128);
            unsigned char nMemTemp_out[720*574];
            unsigned char binary_out[720*574];

            the varibles of nMemTemp_out and binary_out defined as a globle varible allocated in SDRAM,I want to process it in inter ram,so,I defined a varible nSegmentTemp

            #pragma DATA_SECTION(nSegmentTemp, ".INTPROCBUFF");
            #pragma DATA_ALIGN(nSegmentTemp,128);
            unsigned char nSegmentTemp[720];

            the nSegmentTemp is allocated in the inter ram. tha data of nSegmentTemp is evaluated by the function of  ICETEKDM642PCIImagebinary()

           this statements are in another file.  The compiling is passed,When i track this step by step ,I watch the memory

           m_nID=DAT_copy(nSegmentTemp,nMemTemp_out+i*capLinePitch,720);

           The content of the nSegmentTemp is not copied to the nMemTemp_out, the content of the nMemTemp_out is not changed.Why?

           And this statement: IMG_perimeter(nMemTemp_out+i*capLinePitch,720,binary_out+i*capLinePitch);

           This invoke is right? I mean the method of line by line to process this video?

         Thank you very much!