题解 | #使用8线-3线实现16线-4线优先编码器#

`timescale 1ns/1ns
module encoder_83(
   input      [7:0]       I   ,
   input                  EI  ,
   
   output wire [2:0]      Y   ,
   output wire            GS  ,
   output wire            EO    
);
assign Y[2] = EI & (I[7] | I[6] | I[5] | I[4]);
assign Y[1] = EI & (I[7] | I[6] | ~I[5]&~I[4]&I[3] | ~I[5]&~I[4]&I[2]);
assign Y[0] = EI & (I[7] | ~I[6]&I[5] | ~I[6]&~I[4]&I[3] | ~I[6]&~I[4]&~I[2]&I[1]);

assign EO = EI&~I[7]&~I[6]&~I[5]&~I[4]&~I[3]&~I[2]&~I[1]&~I[0];

assign GS = EI&(I[7] | I[6] | I[5] | I[4] | I[3] | I[2] | I[1] | I[0]);
//assign GS = EI&(| I);
         
endmodule

module encoder_164(
   input      [15:0]      A   ,
   input                  EI  ,
   
   output wire [3:0]      L   ,
   output wire            GS  ,
   output wire            EO    
);

    wire [3:0] Y_high;
    wire [3:0] Y_low;
    wire GS_high;
    wire GS_low;
    wire EO_high;
    wire EO_low;

    encoder_83 u1_encoder_83(//高位
        .I(A[15:8]),
        .EI(EI),
        .Y(Y_high),
        .GS(GS_high),
        .EO(EO_high)    
            );
    encoder_83 u2_encoder_83(//低位
        .I(A[7:0]),
        .EI(EO_high),
        .Y(Y_low),
        .GS(GS_low),
        .EO(EO_low)    
            );

        assign EO = EO_low;
        assign GS = GS_high | GS_low;
        assign L[3] = GS_high;
        assign L[2] = Y_high[2] | Y_low[2];
        assign L[1] = Y_high[1] | Y_low[1];
        assign L[0] = Y_high[0] | Y_low[0];


endmodule