alu64bit.sv

// 64-bit ALU template
module alu64bit (
    input logic [63:0] a,    // Input bit a
    input logic [63:0] b,    // Input bit b
    input logic cin,         // Carry in
    input logic [1:0] op,    // Operation
    output logic [63:0] s,   // Output S
    output logic cout        // Carry out
);

logic [62:0] carry;
//first ALU
alu1bit alu_0 (
    .a(a[0]),
    .b(b[0]),
    .cin(cin),
    .op(op),
    .s(s[0]),
    .cout(carry[0])
);
//middle ALU
genvar i;
generate
    for (i=1; i<63; i++)
    begin
        alu1bit alu_inst(
            .a(a[i]),
            .b(b[i]),
            .cin(carry[i-1]),
            .op(op),
            .s(s[i]),
            .cout(carry[i]));
    end
endgenerate

//last ALU
alu1bit alu_63 (
    .a(a[63]),
    .b(b[63]),
    .cin(carry[62]),
    .op(op),
    .s(s[63]),
    .cout(cout)
);


endmodule