aludec.sv

module aludec(input  logic [5:0] funct,
              input  logic [1:0] aluop,
              output logic [2:0] alucontrol);

  always_comb
    case(aluop)
      2'b00: alucontrol <= 3'b010;  // add (for lw/sw/addi)
      2'b01: alucontrol <= 3'b110;  // sub (for beq)
      default: case(funct)          // R-type instructions
          6'b100000: alucontrol <= 3'b010; // add
          6'b100010: alucontrol <= 3'b110; // sub
          6'b100100: alucontrol <= 3'b000; // and
          6'b100101: alucontrol <= 3'b001; // or
          6'b101010: alucontrol <= 3'b111; // slt
          default:   alucontrol <= 3'bxxx; // ???
        endcase
    endcase
endmodule