Question

我为加法器做了一个设计但结果是错误的。

module CLA16(A, B, Ci, S, Co, PG1, GG1);

input [15:0] A;
input [15:0] B;
input Ci;
output [15:0] S;
output Co;
output PG1;
output GG1;

wire [3:0] GG;
wire [3:0] PG;
wire [3:1] C;
wire Ci;

CLALogic CarryLogic_2 (PG[3:0], GG[3:0], Ci, C[3:1], Co, PG1, GG1);

// 4bit    A     B       Ci     S   PG        GG    Co
CLA4 u0 (A[3:0], B[3:0], Ci, S[3:0],PG[0], GG[0]);
CLA4 u1 (A[7:4], B[7:4], C[1],  S[7:4], PG[1], GG[1]);
CLA4 u2 (A[11:8], B[11:8], C[2], S[11:8], PG[2], GG[2]);
CLA4 u3 (A[15:12], B[15:12], C[3], S[15:12], PG[3], GG[3]);

endmodule

module CLA4(A, B, Ci, S, P, G);
   input [3:0] A;
   input [3:0] B;
   input Ci;
   output [3:0] S;
   //output Co;
   output P;
   output G;
   wire Ci;
   wire [3:0] G;
   wire [3:0] P;
   wire [3:1] C;

   CLALogic CarryLogic (G, P, Ci, C, Co, PG, GG);
   GPFullAdder FA0 (A[0], B[0], Ci, G[0], P[0], S[0]);
   GPFullAdder FA1 (A[1], B[1], C[1], G[1], P[1], S[1]);
   GPFullAdder FA2 (A[2], B[2], C[2], G[2], P[2], S[2]);
   GPFullAdder FA3 (A[3], B[3], C[3], G[3], P[3], S[3]);

endmodule

module CLALogic (G, P, Ci, C, Co, PG, GG);
   input [3:0] G;
   input [3:0] P;
   input Ci;
   output [3:1] C;
   output Co;
   output PG;
   output GG;

   wire GG_int;
   wire PG_int;

   assign C[1] = G[0] | (P[0] & Ci);
   assign C[2] = G[1] | (P[1] & G[0])| (P[1] & P[0] & Ci);
   assign C[3] = G[2] | (P[2] & G[1]) | (P[2] & P[1] & G[0])| (P[2] & P[1] & P[0] & Ci);


   assign PG_int = P[3] & P[2] & P[1] & P[0];
   assign GG_int = G[3] | (P[3] & G[2]) | (P[3] & P[2] & G[1]) | (P[3] & P[2] & P[1] & G[0]);
   assign Co = GG_int | (PG_int & Ci);
   assign PG = PG_int;
   assign GG = GG_int;

   endmodule

   module GPFullAdder(X, Y, Cin, G, P, Sum);
      input X;
      input Y;
      input Cin;
      output G;
      output P;
      output Sum;

      wire P_int;

      assign G = X & Y;
      assign P = P_int;
      assign P_int = X ^ Y;
      assign Sum = P_int ^ Cin;
  endmodule

测试平台

   module tb_CLA16;

   reg [15:0] A;
   reg [15:0] B;
   reg Ci;
   wire [15:0] S;
   wire Co;
   wire PG;
   wire GG;

   wire [15:0] G;
   wire [15:0] P;
   wire [15:1] C;

 //CLA4 u0(A, B, Ci, S, Co, PG, GG);
  CLA16 u1(A, B, Ci, S, Co);

   initial begin
   A = 16'b0000_1010_1010_1000;
   B = 16'b0000_0100_0000_0000;
   Ci = 1;

   #100

   A = 16'b0000_0000_1010_1000;
   B = 16'b0000_0100_0110_0000;
   Ci = 0;

   #100
   A = 16'd1552;
   B = 16'd0713;
   Ci = 0;

   end

   endmodule

我的结果波形：

if a,b :  168+1120   answer is 1288.

binary number          0000_010**1**_0000_1000  = 1288
but my simulation is   0000_010**0**_0000_1000   wrong

也

a,b is 1552+713 answer is 2265.

    binary number      000**0**_100**0**_110**1**_100**1** is answer number
but my simulations is  000**0**_100**1**_111**0**_100**1** .

16位加法器有四个模块，但不同的s [4] s [7] s [11]。

如何更改代码？我认为16adder模块是个问题。请告诉我。

Answer 1

如果您对信号和端口使用更明确的命名，我怀疑有两个错误可以更容易检测到。例如。 prop，propUp代替P，PG。

第一：

module CLA4(A, B, Ci, S, P, G);

应该是

module CLA4(A, B, Ci, S, PG, GG);

您还需要更改output行。

第二

CLALogic CarryLogic_2 (PG[3:0], GG[3:0], Ci, C[3:1], Co, PG1, GG1);

应该是

CLALogic CarryLogic_2 (GG[3:0], PG[3:0], Ci, C[3:1], Co, PG1, GG1);

工作示例：https://www.edaplayground.com/x/4uMa

如何更改代码。 16位CLA（carry-look.ahead adder）verilog代码模拟

1 个答案: