用verilog写一个加法器

可以使用以下代码来设计一个8位十进制加法器：

module decimal_adder(input [7:] a, b, output [7:] sum);
reg [3:] carry;

always @(*) begin
sum[] = a[] ^ b[] ^ carry[];
sum[1] = a[1] ^ b[1] ^ carry[1];
sum[2] = a[2] ^ b[2] ^ carry[2];
sum[3] = a[3] ^ b[3] ^ carry[3];
sum[4] = a[4] ^ b[4] ^ carry[4];
sum[5] = a[5] ^ b[5] ^ carry[5];
sum[6] = a[6] ^ b[6] ^ carry[6];
sum[7] = a[7] ^ b[7] ^ carry[7];

carry[] = (a[] & b[]) | (a[] & carry[]) | (b[] & carry[]);
carry[1] = (a[1] & b[1]) | (a[1] & carry[1]) | (b[1] & carry[1]) | (carry[] & (a[] ^ b[]));
carry[2] = (a[2] & b[2]) | (a[2] & carry[2]) | (b[2] & carry[2]) | (carry[1] & (a[1] ^ b[1]));
carry[3] = (a[3] & b[3]) | (a[3] & carry[3]) | (b[3] & carry[3]) | (carry[2] & (a[2] ^ b[2]));
carry[4] = (a[4] & b[4]) | (a[4] & carry[4]) | (b[4] & carry[4]) | (carry[3] & (a[3] ^ b[3]));
carry[5] = (a[5] & b[5]) | (a[5] & carry[5]) | (b[5] & carry[5]) | (carry[4] & (a[4] ^ b[4]));
carry[6] = (a[6] & b[6]) | (a[6] & carry[6]) | (b[6] & carry[6]) | (carry[5] & (a[5] ^ b[5]));
carry[7] = (a[7] & b[7]) | (a[7] & carry[7]) | (b[7] & carry[7]) | (carry[6] & (a[6] ^ b[6]));
end
endmodule

这个加法器使用了一个4位的进位寄存器，用于存储每一位的进位。在每一位的计算中，使用异或门计算出该位的和，使用与门和或门计算出该位的进位，并将进位存储到进位寄存器中。最终得到的和就是两个输入数的十进制和。