测试给出 x 而不是数字的 8 位全加器

Question

对于一所大学 class，我们被告知要从 full_adder 中进行 8 位 full_adder 和测试。我相信主要代码是正确的，但我可能在测试中犯了一些错误。如果我能在 x 输出方面得到一些帮助，我将不胜感激。

这里是8位加法器：

module adder_8bit (A1, B1, A2, B2, A3, B3, A4, B4, A5, B5, A6, B6, A7, B7, A8, B8, C_IN,
S_OUT1, C_OUT1, S_OUT2, C_OUT2, S_OUT3, C_OUT3, S_OUT4, C_OUT4, S_OUT5, C_OUT5, S_OUT6, C_OUT6, S_OUT7, C_OUT7, S_OUT8, C_OUT8,
S0, D0, C0, S1, D1, C1, S2, D2, C2, S3, D3, C3, S4, D4, C4, S5, D5, C5, S6, D6, C6, S7, D7, C7 );

    input A1, B1, A2, B2, A3, B3, A4, B4, A5, B5, A6, B6, A7, B7, A8, B8, C_IN;

    inout C_OUT1, S_OUT2, C_OUT2, S_OUT3, C_OUT3, S_OUT4, C_OUT4, 
    S_OUT5, C_OUT5, S_OUT6, C_OUT6, S_OUT7, C_OUT7, S_OUT8,S0, D0, C0, S1, D1, C1, 
    S2, D2, C2, S3, D3, C3, S4, D4, C4, S5, D5, C5, S6, D6, C6, S7, D7, C7;

    output S_OUT1, C_OUT8;

    assign S0 = A1 ^ B1;
    assign C0 = A1 & B1;
    assign S_OUT1 = S0 ^ C_IN;
    assign D0 = S0 & C_IN;
    assign C_OUT1 = D0 | C0;
    assign S1 = A2 ^ B2;
    assign C1 = A2 & B2;
    assign S_OUT2 = S1 ^ C_OUT1;
    assign D1 = S1 & C_OUT1;
    assign C_OUT2 = D1 | C1;
    assign S2 = A3 ^ B3;
    assign C2 = A3 & B3;
    assign S_OUT3 = S2 ^ C_OUT2;
    assign D2 = S2 & C_OUT2;
    assign C_OUT3 = D2 | C2;
    assign S3 = A4 ^ B4;
    assign C3 = A4 & B4;
    assign S_OUT4 = S3 ^ C_OUT3;
    assign D3 = S3 & C_OUT3;
    assign C_OUT4 = D3 | C3;
    assign S4 = A5 ^ B5;
    assign C4 = A5 & B5;
    assign S_OUT5 = S4 ^ C_OUT4;
    assign D4 = S4 & C_OUT4;
    assign C_OUT5 = D4 | C4;
    assign S5 = A6 ^ B6;
    assign C5 = A6 & B6;
    assign S_OUT6 = S5 ^ C_OUT5;
    assign D5 = S5 & C_OUT5;
    assign C_OUT6 = D5 | C5;
    assign S6 = A7 ^ B7;
    assign C6 = A7 & B7;
    assign S_OUT7 = S6 ^ C_OUT6;
    assign D6 = S6 & C_OUT6;
    assign C_OUT7 = D6 | C6;
    assign S7 = A8 ^ B8;
    assign C7 = A8 & B8;
    assign S_OUT8 = S7 ^ C_OUT7;
    assign D7 = S7 & C_OUT7;
    assign C_OUT8 = D7 | C_OUT7;

endmodule

这是测试

`include "adder_8bit.v"
`timescale 1ps/1ps
module adder_8bit_test;

    reg A1, B1, A2, B2, A3, B3, A4, B4, A5, B5, A6, B6, A7, B7, A8, B8, C_IN;

    wire C_OUT1, S_OUT2, C_OUT2, S_OUT3, C_OUT3, S_OUT4, C_OUT4, 
    S_OUT5, C_OUT5, S_OUT6, C_OUT6, S_OUT7, C_OUT7, S_OUT8, S0, D0, C0, S1, D1, C1, 
    S2, D2, C2, S3, D3, C3, S4, D4, C4, S5, D5, C5, S6, D6, C6, S7, D7, C7,
    S_OUT1, C_OUT8;

    adder_8bit UUT (.A1, .B1, .A2, .B2, .A3, .B3, .A4, .B4, .A5, .B5, .A6, .B6, .A7, .B7, .A8, .B8, 
    .S_OUT1, .C_OUT1, .S_OUT2, .C_OUT2, .S_OUT3, .C_OUT3, .S_OUT4, .C_OUT4, .S_OUT5, .C_OUT5, .S_OUT6, .C_OUT6, .S_OUT7, .C_OUT7, .S_OUT8, .C_OUT8,
    .S0, .D0, .C0, .S1, .D1, .C1, .S2, .D2, .C2, .S3, .D3, .C3, .S4, .D4, .C4, .S5, .D5, .C5, .S6, .D6, .C6, .S7, .D7, .C7 );

    initial begin
        $display("Start of Test.");
        $dumpfile("adder_8bit.vcd");
        $dumpvars(0, adder_8bit_test);
        {A1, B1, C_IN} = 3'b000; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT1, C_OUT1);
        {A1, B1, C_IN} = 3'b001; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT2, C_OUT2);
        {A1, B1, C_IN} = 3'b010; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT3, C_OUT3);
        {A1, B1, C_IN} = 3'b011; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT4, C_OUT4);
        {A1, B1, C_IN} = 3'b100; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT5, C_OUT5);
        {A1, B1, C_IN} = 3'b101; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT6, C_OUT6);
        {A1, B1, C_IN} = 3'b110; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT7, C_OUT7);
        {A1, B1, C_IN} = 3'b111; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT8, C_OUT8);
        $display("End of Test.");
    end
endmodule

Answer 1

我收到编译警告；如果你不这样做，你应该在 edaplayground 上注册一个免费帐户，并尝试在多个模拟器上编译你的代码。

您没有驱动您的 C_IN 输入。变化：

adder_8bit UUT (.A1, .B1, .A2, .B2, .A3, .B3, .A4, .B4, .A5, .B5, .A6, .B6, .A7, .B7, .A8, .B8,

至：

adder_8bit UUT (.A1, .B1, .A2, .B2, .A3, .B3, .A4, .B4, .A5, .B5, .A6, .B6, .A7, .B7, .A8, .B8, .C_IN,

您还需要将所有输入设置为已知值。您只设置 A1、B1 和 C_IN.

A2、A3等，都是未知数(x)。也许你打算使用这样的东西：

    {A1, B1, C_IN} = 3'b000; #100; $display("%b + %b + %b = %b%b", A1, B1, C_IN, S_OUT1, C_OUT1);
    {A2, B2, C_IN} = 3'b001; #100; $display("%b + %b + %b = %b%b", A2, B2, C_IN, S_OUT2, C_OUT2);

其他注意事项：

我认为你不需要在那里使用 inout。
如果您使用 8 位信号，您的代码会简单得多：reg [7:0] A;

测试给出 x 而不是数字的 8 位全加器

Test for a 8-bit full adder giving x instead of numbers

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