题解 | #优先编码器Ⅰ#

`timescale 1ns/1ns

module encoder_83(
   input      [7:0]       I   ,
   input                  EI  ,
   
   output wire [2:0]      Y   ,
   output wire            GS  ,
   output wire            EO    
);
reg [2:0]Y1;
assign EO=EI&(~(EI&&I));
assign GS=EI&(EI&I);
assign Y=Y1;

always@(*)
    if(EI==1'b1)begin
casez(I)
8'b1???????:Y1=3'b111;
8'b01??????:Y1=3'b110;
8'b001?????:Y1=3'b101;
8'b0001????:Y1=3'b100;
8'b00001???:Y1=3'b011;
8'b000001??:Y1=3'b010;
8'b0000001?:Y1=3'b001;
8'b00000001:Y1=3'b000;
endcase 
end else Y1=3'b000;
endmodule