how to optimize my for loops

Hi, JIT accelerator is not working for me, and currently, this piece of code looks like it's going to take about 3 hours...

My professor wrote a similar piece of code with the same usage and it completed within a few minutes... I'm really quite confused.

wav1 and wav2 are both 1x2601900 double.

basically, wav1 is a marker file for wav2, so I know where to cut and add to tmp.

function tmp = AddWaveform(Wav1,Wav2)
    tmp=zeros(1,2090);
    for i=1:1244
          x=1;
          flag=0;
      while(flag==0)
               if(  mod(Wav2((i-1)*2090+x),7500)==0  )
          tmp = tmp + Wav1((i-1)*2090+x : (i-1)*2090+x+2089);
          flag=1;
        end
        x=x+1;
          end
          end