#define M 4
#define N 4

main()
{
     int *a,k;
     a = (int *) 0x10000;
     k=conv(a);
}

int  conv(int a[M][N])
{
    int i,j,k;
    for(i=1; i<(M-1); i++) {
	for(j=1; j<(N-1); j++) {

		k = a[i-1][j-1] +
		    a[i-1][j] +
		    a[i-1][j+1] +
		    a[i][j-1] +
		    a[i][j+1] +
		    a[i+1][j-1] +
		    a[i+1][j] +
		    a[i+1][j+1];
		k = k>>3; /* div 8 */
		k = k + a[i][j];
		a[i][j] = k >> 1; /* finish normalizing */
	    }
    }
    return k;
}