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// ============================================================================

//        __

//   \\__/ o\    (C) 2020  Robert Finch, Waterloo

//    \  __ /    All rights reserved.

//     \/_//     robfinch@finitron.ca

//       ||

//

//      DPDEncode.sv

//

// An encoding described in:

//      Densely Packed Decimal Encoding, by Mike Cowlishaw, in

//      IEE Proceedings – Computers and Digital Techniques, ISSN 1350-2387,

//      Vol. 149, No. 3, pp102–104, IEE, May 2002

//

// See: http://speleotrove.com/decimal/DPDecimal.html

//

// BSD 3-Clause License

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// 1. Redistributions of source code must retain the above copyright notice, this

//    list of conditions and the following disclaimer.

//

// 2. Redistributions in binary form must reproduce the above copyright notice,

//    this list of conditions and the following disclaimer in the documentation

//    and/or other materials provided with the distribution.

//

// 3. Neither the name of the copyright holder nor the names of its

//    contributors may be used to endorse or promote products derived from

//    this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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//

// ============================================================================

module DPDEncode(i, o);

input [11:0] i;

output [9:0] o;

wire a,b,c,d,e,f,g,h,ii,j,k,m;

wire p,q,r,s,t,u,v,w,x,y;

assign {a,b,c,d,e,f,g,h,ii,j,k,m} = i;

assign p = b | (a & j) | (a & f & ii);

assign q = c | (a & k) | (a & g & ii);

assign r = d;

assign s = (f & (~a | ~ii)) | (~a & e & j) | (e & ii);

assign t = g  | (~a & e &k) | (a & ii);

assign u = h;

assign v = a | e | ii;

assign w = a | (e & ii) | (~e & j);

assign x = e | (a & ii) | (~a & k);

assign y = m;

assign o = {p,q,r,s,t,u,v,w,x,y};

endmodule

module DPDEncodeN(i, o);

parameter N=11;

input [N*12-1:0] i;

output [N*10-1:0] o;

genvar g;

generate begin : gDPDEncodeN

        for (g = 0; g < N; g = g + 1)

                DPDEncode u1 (i[g*12+11:g*12],o[g*10+9:g*10]);

end

endgenerate

endmodule