ALU.sv

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: 
// 
// Create Date: 2024/05/01 10:31:41
// Design Name: 
// Module Name: ALU
// Project Name: 
// Target Devices: 
// Tool Versions: 
// Description: 
// 
// Dependencies: 
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 
//////////////////////////////////////////////////////////////////////////////////

`include "defines.svh"

module ALU #(
    parameter DATAWIDTH = 32
)(
    input  logic [DATAWIDTH-1:0]  A,
    input  logic [DATAWIDTH-1:0]  B,
    input  logic [3:0]            ALUControl,
    output logic [DATAWIDTH-1:0]  Result,
    output logic                  isTrue
);

always_comb begin
    Result = 0;
    
    case(ALUControl)
        // 算术运算
        `ALU_ADD:  Result = A + B;
        `ALU_SUB, `ALU_BEQ, `ALU_BNE:  Result = A - B;
        
        // 移位操作
        `ALU_SLL:  Result = A << B[4:0];                // 逻辑左移
        `ALU_SRL:  Result = A >> B[4:0];                // 逻辑右移
        `ALU_SRA:  Result = $signed(A) >>> B[4:0];      // 算术右移
        
        // 逻辑运算
        `ALU_XOR:  Result = A ^ B;
        `ALU_OR:   Result = A | B;
        `ALU_AND:  Result = A & B;
        
        // 比较运算
        `ALU_SLT, `ALU_BLT, `ALU_BGE:  begin  // 有符号比较
            Result = ($signed(A) < $signed(B)) ? 1 : 0;
        end
        `ALU_SLTU, `ALU_BLTU, `ALU_BGEU: begin // 无符号比较
            Result = (A < B) ? 1 : 0;
        end
        
        default: begin
            Result = 32'h0;
        end
    endcase
end

always_comb begin
    isTrue = 1'b0; // 默认值
    case(ALUControl)
        `ALU_BEQ:    begin
                        isTrue = (A == B);
                        $display("Entered ALU_BEQ case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                    end
        `ALU_BNE:    begin
                        isTrue = (A != B);
                        $display("Entered ALU_BNE case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                    end
        `ALU_BLT:    begin
                        isTrue = ($signed(A) < $signed(B));
                        $display("Entered ALU_BLT case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                    end
        `ALU_BLTU:   begin
                        isTrue = (A < B);
                        $display("Entered ALU_BLTU case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                        $display("***** ALU_BLTU: A < B check: A = %h, B = %h", A, B);
                    end
        `ALU_BGE:    begin
                        isTrue = ($signed(A) >= $signed(B));
                        $display("Entered ALU_BGE case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                    end
        `ALU_BGEU:   begin
                        isTrue = (A >= B);
                        $display("Entered ALU_BGEU case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                    end
        default:     begin
                        isTrue = 1'b0;
                        $display("Entered default case: A = %h, B = %h, isTrue = %b", A, B, isTrue);
                        $display("&&& Default case entered!");
                    end
    endcase
end

// 输出最终的 isTrue
always@(* ) begin
$display("                              ");
$display("------------In ALU------------");
$display("ALUControl = %h", ALUControl);
$display("ALU Compare: A = %h, B = %h, Result = %h", A, B, Result);
$display("A < B = %b", (A < B));
$display("ALU isTrue = %b", isTrue);
end

endmodule