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    
);
//I[i]=1 则Y=i
//任意I[i]=1，GS=1
//EI=1时，输出有效
//EI=1 无输入时， EO有效


        assign Y = EI?  (I      == 8'b0000_0001)?3'd0 :
                        (I[7:1] == 7'b0000_001 )?3'd1 :
                        (I[7:2] == 6'b0000_01  )?3'd2 :
                        (I[7:3] == 5'b0000_1   )?3'd3 :
                        (I[7:4] == 4'b0001     )?3'd4 :
                        (I[7:5] == 3'b001      )?3'd5 :
                        (I[7:6] == 2'b01       )?3'd6 :
                        (I[7  ] == 1'b1        )?3'd7 : 3'd0 :
                        3'd0;



assign GS = EI & |I;
assign EO = EI & ~|I;
endmodule