3.22【计组】流水线加法器-EW帮帮网

'实验一

`timescale 1ns / 1ps

/* ALU模块实现两个32bit数的add、sub、and、or、not、slt功能，
但由于Nexy7输入口限制，将num1简化为8位，在过程中再extend成32位，num2作为内部wire自行赋值，此处赋为5
由于最后的结果在top.v中以七段数码管显示，32位结果不用以led在nexy4显示，因此输出32位结果没有问题*/

module alu(
    input wire [2:0] op,
    input wire [7:0] num1,
    output reg [31:0] result
    );
    wire [31:0] num2;
    wire [31:0] sign_extend_num1;
    assign num2=32'h0000_0001;
    assign sign_extend_num1={24'h0,num1};
    
    always@(*)begin
        case(op)
            3'b000:result=sign_extend_num1+num2;
            3'b001:result=sign_extend_num1-num2;
            3'b010:result=sign_extend_num1&num2;
            3'b011:result=sign_extend_num1|num2;
            3'b100:result=~sign_extend_num1;
            3'b101:begin
                if(sign_extend_num1<num2)   result=32'h0000_0001;
                else                        result=32'h0000_0000;
            end
            default:result=32'hxxxx_xxxx;
        endcase
    end
    
endmodule

module display(
    input wire clk,reset,
    input wire [31:0]s,
    output wire [6:0]seg,
    output reg [7:0]ans
    );
    reg [20:0]count;
    reg [3:0]digit; 
    always@(posedge clk,posedge reset)
    if(reset)  
        count = 0;
    else 
        count = count + 1;
       
    always @(posedge clk)
    case(count[20:18])
        0:begin
            ans = 8'b11111110;
            digit = s[3:0];
        end
        
        1:begin
            ans = 8'b11111101;
            digit = s[7:4];
        end

        2:begin
            ans = 8'b11111011;
            digit =s[11:8];
        end
        
        3:begin
            ans = 8'b11110111;
            digit = s[15:12];
        end
        
         4:begin
             ans = 8'b11101111;
             digit = s[19:16];
         end
               
         5:begin
             ans = 8'b11011111;
             digit = s[23:20];
         end
       
         6:begin
             ans = 8'b10111111;
             digit =s[27:24];
         end
               
         7:begin
             ans = 8'b01111111;
             digit = s[31:28];
         end
    endcase
    
    seg7 U4(.din(digit),.dout(seg));
endmodule

module seg7(
    input wire [3:0]din,
    output reg [6:0]dout
    );
 
    always@(*)
    case(din)
        5'h0:dout = 7'b000_0001;
        5'h1:dout = 7'b100_1111;
        5'h2:dout = 7'b001_0010;
        5'h3:dout = 7'b000_0110;
        5'h4:dout = 7'b100_1100;
        5'h5:dout = 7'b010_0100;
        5'h6:dout = 7'b010_0000;
        5'h7:dout = 7'b000_1111;
        5'h8:dout = 7'b000_0000;
        5'h9:dout = 7'b000_0100;
        5'ha:dout = 7'b000_1000;
        5'hb:dout = 7'b110_0000;
        5'hc:dout = 7'b011_0001;
        5'hd:dout = 7'b100_0010;
        5'he:dout = 7'b011_0000;
        5'hf:dout = 7'b011_1000;
        default:dout = 7'b111_1111;        
    endcase

module top(
    input wire [2:0] op,    //手动输入alu
    input wire [7:0] num1,  //手动输入alu
    input wire clk,reset,   //板子上clk、手动rst输入display
    output wire [6:0]seg,   //display输出
    output wire [7:0]ans     //display输出
    );
    wire [31:0] result;      //alu输出进入display
    alu gate1(op,num1,result);
    display gate2(clk,reset,result,seg,ans);
    
endmodule