alu_control.v

/* alu_control.v */
module alu_control(
    input	wire	[5:0]	funct,
    input	wire	[1:0]	aluop,
    output	reg	[2:0]	select
    );
	
	parameter	Rtype 		=	2'b10,
					Radd			=	6'b100000,
					Rsub			=	6'b100010,
					Rand			=	6'b100100,
					Ror			=	6'b100101,
					Rslt			=	6'b101010;
	
	parameter	lwsw			=	2'b00,
					Itype			=	2'b01,
					xis			=	6'bXXXXXX;
		
	
	parameter	ALUadd		=	3'b010,
					ALUsub		=	3'b110,
					ALUand		=	3'b000,
					ALUor			=	3'b001,
					ALUslt		=	3'b111;
					
	parameter	unknown		=	2'b11,
					ALUx			=	3'b011;
	
	initial
		select <= 0;
	
	always@* begin
		if (aluop == Rtype)
		 begin
			case(funct)
				Radd:			select <= ALUadd;
				Rsub:			select <= ALUsub;
				Rand:			select <= ALUand;
				Ror:			select <= ALUor;
				Rslt:			select <= ALUslt;
				default:		select <= ALUx;
			endcase
	    end
		 
		else if (aluop == lwsw)
       begin
			select <= ALUadd;
		 end
		
		else if (aluop == Itype)
       begin		
		   select <= ALUsub;
		 end
		
		else if (aluop == unknown)
	    begin	
   		select <= ALUx;
		 end
		
		else
		 begin
			select <= select;			
	    end	
	end
endmodule // alu_control