Making normxcorr2 function efficient

Hello the problem I'm facing is that for calculations with large matrix, the normxcorr2 takes much time.So is there be any way of doing the function for a limited range.Pls see the code that I have attached.I want the function normxcorr2 to return only the highlighted part in the image(which is time efficient).

tmp1=magic(5)
  tmp2=magic(6)
  cnorm=normxcorr2(tmp1,tmp2)
  MinLagR = -2; MaxLagR =1; 
  MinLagC = -2; MaxLagC =2; 

    zerolagr=size(cnorm,1)-size(tmp2,1)+1;
    zerolagc=size(cnorm,2)-size(tmp2,2)+1;
    c=cnorm(zerolagr,zerolagc)
    cx=cnorm(zerolagr+MinLagR:zerolagr+MaxLagR,zerolagc+MinLagC:zerolagc+MaxLagC )