verilog实现四位全加器的代码与仿真设计
时间: 2023-06-19 11:09:09 浏览: 145
以下是基于 Verilog 的四位全加器的代码实现及仿真设计。
```
module full_adder(
input a,
input b,
input cin,
output sum,
output cout
);
assign sum = a ^ b ^ cin;
assign cout = (a & b) | (a & cin) | (b & cin);
endmodule
module four_bit_adder(
input [3:0] a,
input [3:0] b,
input cin,
output [3:0] sum,
output cout
);
wire c1, c2, c3;
full_adder fa0(a[0], b[0], cin, sum[0], c1);
full_adder fa1(a[1], b[1], c1, sum[1], c2);
full_adder fa2(a[2], b[2], c2, sum[2], c3);
full_adder fa3(a[3], b[3], c3, sum[3], cout);
endmodule
module four_bit_adder_tb;
reg [3:0] a;
reg [3:0] b;
reg cin;
wire [3:0] sum;
wire cout;
four_bit_adder test(a, b, cin, sum, cout);
initial begin
$dumpfile("four_bit_adder_tb.vcd");
$dumpvars(0, four_bit_adder_tb);
// Test case 1: 2 + 3 = 5
a = 2;
b = 3;
cin = 0;
#10;
$display("Test case 1: %d + %d = %d", a, b, sum);
$display("Carry out: %d", cout);
// Test case 2: 10 + 5 = 15
a = 10;
b = 5;
cin = 0;
#10;
$display("Test case 2: %d + %d = %d", a, b, sum);
$display("Carry out: %d", cout);
// Test case 3: 8 + 8 = 0, carry out 1
a = 8;
b = 8;
cin = 0;
#10;
$display("Test case 3: %d + %d = %d", a, b, sum);
$display("Carry out: %d", cout);
// Test case 4: 7 + 9 = 0, carry out 1
a = 7;
b = 9;
cin = 0;
#10;
$display("Test case 4: %d + %d = %d", a, b, sum);
$display("Carry out: %d", cout);
// Test case 5: 15 + 1 = 0, carry out 1
a = 15;
b = 1;
cin = 0;
#10;
$display("Test case 5: %d + %d = %d", a, b, sum);
$display("Carry out: %d", cout);
$finish;
end
endmodule
```
以上代码中,`full_adder` 模块实现了单个全加器的功能,`four_bit_adder` 模块则通过四个全加器的级联实现了四位全加器的功能。测试模块 `four_bit_adder_tb` 中包含了五个测试用例,用于验证四位全加器的正确性。
在仿真中,可以使用 Verilog 模拟器,例如 ModelSim 或 Vivado 进行仿真。在仿真中,将 `four_bit_adder_tb` 作为顶层模块进行仿真即可。仿真结果将被输出到 `four_bit_adder_tb.vcd` 文件中。