题解 | #串行进位加法器#
串行进位加法器
https://www.nowcoder.com/practice/83c5850805004b6d8c48742f582f304a
`timescale 1ns/1ns
module add_half(
input A ,
input B ,
output wire S ,
output wire C
);
assign S = A ^ B;
assign C = A & B;
endmodule
/***************************************************************/
module add_full(
input A ,
input B ,
input Ci ,
output wire S ,
output wire Co
);
wire c_1;
wire c_2;
wire sum_1;
add_half add_half_1(
.A (A),
.B (B),
.S (sum_1),
.C (c_1)
);
add_half add_half_2(
.A (sum_1),
.B (Ci),
.S (S),
.C (c_2)
);
assign Co = c_1 | c_2;
endmodule
/******************************************************************/
module add_4(
input [3:0] A ,
input [3:0] B ,
input Ci ,
output wire [3:0] S ,
output wire Co
);
wire [4:1] Co_add4;
add_full inst0(
.A (A[0]) ,
.B (B[0]) ,
.Ci (Ci) ,
.S (S[0]) ,
.Co (Co_add4[1])
);
add_full inst1(
.A (A[1]) ,
.B (B[1]) ,
.Ci (Co_add4[1]) ,
.S (S[1]) ,
.Co (Co_add4[2])
);
add_full inst2(
.A (A[2]) ,
.B (B[2]) ,
.Ci (Co_add4[2]) ,
.S (S[2]) ,
.Co (Co_add4[3])
);
add_full inst3(
.A (A[3]) ,
.B (B[3]) ,
.Ci (Co_add4[3]) ,
.S (S[3]) ,
.Co (Co_add4[4])
);
assign Co = Co_add4[4];
endmodule
