题解 | #使用8线-3线Ⅰ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 [2:0]Y_1;
    wire GS_1;
    wire EO_1;
    encoder_83 e_1(
        .I(A[15:8]),
        .EI(EI),
        .Y(Y_1),
        .GS(GS_1),
        .EO(EO_1)
    );

    wire [2:0]Y_0;
    wire GS_0;
    wire EO_0;
    encoder_83 e_0(
        .I(A[7:0]),
        .EI(EO_1),
        .Y(Y_0),
        .GS(GS_0),
        .EO(EO_0)
    );

assign GS = GS_1 | GS_0;
assign EO = EO_0;
assign L[3] = GS_1;
assign L[2] = Y_1[2] | Y_0[2];
assign L[1] = Y_1[1] | Y_0[1];
assign L[0] = Y_1[0] | Y_0[0];

endmodule

更考察的是基础数电知识中的级联，只不过当时是划线连接，现在是用代码连接