module array_mult(x,y,p);
    input [3:0] x;
    input [3:0] y;
    output [7:0] p;
    wire [2:0] row0, row1, row2, row3, c0, c1, c2, c3;

    /* generate first row of products */
    assign row0[2] = x[2] & y[0];
    assign row0[1] = x[1] & y[0];
    assign row0[0] = x[0] & y[0]; 
    assign p[0] = row0[0];
    assign c0 = 3'b000;
    multrow p0(row0,x,y[1],y[0],c0,row1,c1);
    assign p[1] = row1[0];
    multrow p1(row1,x,y[2],y[1],c1,row2,c2);
    assign p[2] = row2[0];
    multrow p2(row2,x,y[3],y[2],c2,row3,c3);
    assign p[3] = row3[0];
    lastrow l({x[3] & y[3],row3[2:1]},c3,p[6:4],p[7]);
endmodule