8-bit adder help with my current code.

[nfavenom]

i am designing an 8 bit full adder and this is what i have so far but im not getting the correct output i would appreciate if anyone could help me out.


// 1-bit full_adder
module fulladd(sum, c_out, a, b, c_in);

// I/O port declarations
output sum, c_out;
input a, b, c_in;

// Internal nets
wire s1, c1, c2;

// Instantiate logic gate primatives
xor (s1, a, b);
and (c1, a, b);

xor (sum, s1, c_in);
and (c2, s1, c_in);

or (c_out, c2, c_in);

endmodule

// Define a 8-bit binary adder
module fulladd8(sum, c_out, a, b, c_in);

// I/O port declarations
output [7:0] sum;
output c_out;
input [7:0] a, b;
input c_in;

// Internal nets
wire c1, c2, c3,c4,c5,c6,c7;

// Instantiate four 1-bit full adders
fulladd fa0(sum[0], c1, a[0], b[0], c_in);
fulladd fa1(sum[1], c2, a[1], b[1], c1);
fulladd fa2(sum[2], c3, a[2], b[2], c2);
fulladd fa3(sum[3], c4, a[3], b[3], c3);
fulladd fa4(sum[4], c5, a[4], b[4], c4);
fulladd fa5(sum[5], c6, a[5], b[5], c5);
fulladd fa6(sum[6], c7, a[6], b[6], c6);
fulladd fa7(sum[7], c_out, a[7], b[7], c7);
endmodule

 

[lostinxlation]

or (c_out, c2, c_in);

Highlighten in bold isn't correct.

 

[happylbd]

i think code of "c_out" can write ao follow:
and(t1 , a , b);
and(t2 , a , c_in);
and(t3 , b , c_in);
or(c_out , t1, t2, t3);