'generic with striding pointers
  'def typ float
  typedef float typ
  '
  function MatMul(typ *r,*a,*b, int n=4) 'NxN MATRIX : N=1..
  ============================================================
  int ystep=sizeof typ
  int xstep=n*sizeof typ
  int i,j,k
  sys px
  for i=1 to n
    px=@a
    for j=1 to n
      r=0
      for k=1 to n
        r+=(a*b)
        @a+=xstep
        @b+=ystep
      next
      @r+=ystep
      px+=ystep
      @a=px
      @b-=xstep
    next
    @a-=xstep
    @b+=xstep
  next
  end function