Unknown verilog error 'expecting "endmodule"'

Question

In verilog I have an error that I can't get past. this is the first bit of the code then the last bit

 module Decoder(op,funct,aluop,mwr,mreg,mrd,alusrc,regdst,regwr,btype);
  input[5:0] op,funct;
  output[2:0] aluop;
  output[1:0] btype;
  output mwr,mreg,mrd,alusrc,regdst,regwr;
  wire aluop,mwr,mreg,mrd,alusrc,regdst,regwr,btype;
  case(op)
      6'b000000: begin
          case(funct)
              6'b001010:
                  assign aluop = 3'b010;
              6'b001100:
                  assign aluop = 3'b111;
              6'b010001:
                  assign aluop = 3'b011;
              default:
                  assign aluop = 3'b000;          
          endcase
          assign btype = 2'b00;
          assign mwr = 1'b0;
          assign mreg = 1'b0;
          assign mrd = 1'b0;
          assign alusrc = 1'b0;
          assign regdst = 1'b1;
          assign regwr = 1'b1;
          end

...

  default: begin
      assign aluop = 3'b000;
        assign mwr = 0;
        assign mreg = 0;
        assign mrd = 0;
        assign alusrc = 0;
        assign btype = 2'b00;
        assign regdst = 0;
        assign regwr = 0;
        end
endcase

endmodule

it keeps giving me the following errors

Error (10170): Verilog HDL syntax error at Decoder.v(7) near text "case"; expecting "endmodule" Error (10170): Verilog HDL syntax error at Decoder.v(14) near text "6"; expecting "endmodule"

It also does this at every end statement and default and endcase

I have no idea why it's doing this, I'm fairly new to verilog.

thanks in advance

Answer 1

I believe you're only allowed to use a case statement or if/else inside of an always block. I'm not sure why your error message doesn't say something a little more helpful, but that is likely to be the problem.

Try rewriting your code like the following:

//change wire types to reg type

always @*
begin
  case (op)
    6'b000000: begin
      aluop = 3'b000
    end
    ...
  endcase
end