alu.v.bak

verilog hdl经典例程

`define plus 3'd0
`define minus 3'd1
`define band 3'd2
'define bor 3'd3
`define unegate 3'd4
module alu(out,opcode,a,b);
output[7:0] out;
reg [7:0] out;
input [2:0] opcode;
input [7:0] a,b;
always@(opcode or a or b)
begin
  case(opcode)
  `plus:out=a+b;
  `minus:out=a-b;
  `band:out=a&b;
  `bor:out=a|b;
  `unegate:out=~a;
  default:out=8'hx;
  endcase
  end
endmodule