function y=lconv(g,x)
  szg=length(g);szx=length(x);szy=szg+szx-1;
  y=zeros(1,szy);
  for t=1:szx,
    for u=1:szg,
      y(u+t-1)=y(u+t-1)+g(u)*x(t);
    end,
  end,
endfunction;

//Change to your directory & call once
save('c:\Program Files\scilab-4.0-rc1\macros\mylib\lconv.bin', lconv);
//Example
lconv([4,2,1,0.7],[1,2,3,4])