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alu_decoder.v
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alu_decoder.v
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`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:
// Engineer:
//
// Create Date: 03/04/2023 08:02:24 AM
// Design Name:
// Module Name: alu_decoder
// Project Name:
// Target Devices:
// Tool Versions:
// Description:
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module alu_decoder(
input wire [1:0] alu_op, // 2-bit ALU operation code input
input wire [2:0] funct3, // 3-bit function code input
input wire op5, funct7, // 1-bit opcode 5 and 7 inputs
output reg [2:0] alu_control // 3-bit ALU control output
);
wire [6:0] sel = {alu_op, funct3, op5, funct7}; // Concatenate the inputs for the select statement
localparam [2:0] ADD = 3'b000, // Local parameter for ADD operation
SHL = 3'b001, // Local parameter for SHL operation
SUB = 3'b010, // Local parameter for SUB operation
NOTUSED = 3'b011, // Local parameter for UNUSED operation
XOR = 3'b100, // Local parameter for XOR operation
SHR = 3'b101, // Local parameter for SHR operation
OR = 3'b110, // Local parameter for OR operation
AND = 3'b111; // Local parameter for AND operation
always @(*) begin
casex (sel) // Use the concatenated value as selector
7'b00_???_??: alu_control = ADD; // lw, sw instructions - set to ADD
7'b01_000_??, 7'b01_001_??, 7'b01_100_??: // beq, bnq, blt - set to SUB
alu_control = SUB;
7'b10_000_00, 7'b10_000_01, 7'b10_000_10: // add, addi, sll - set to ADD
alu_control = ADD;
7'b10_000_11: alu_control = SUB; // sub instruction - set to SUB
7'b10_001_??: alu_control = SHL; // shl instruction - set to SHL
7'b10_100_??: alu_control = XOR; // xor instruction - set to XOR
7'b10_101_??: alu_control = SHR; // shr instruction - set to SHR
7'b10_110_??: alu_control = OR; // or instruction - set to OR
7'b10_111_??: alu_control = AND; // and instruction - set to AND
default:
alu_control = ADD; // Default to ADD if no match
endcase
end
endmodule