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

//        __

//   \\__/ o\    (C) 2020-2022  Robert Finch, Waterloo

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

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//

//      DFPCompare96.sv

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

import DFPPkg::*;

module DFPCompare96(a, b, o);

input DFP96 a;

input DFP96 b;

output reg [11:0] o ='d0;

localparam N=34;                        // number of BCD digits

parameter TRUE = 1'b1;

parameter FALSE = 1'b0;

DFP96U au;

DFP96U bu;

DFPUnpack96 u00 (a, au);

DFPUnpack96 u01 (b, bu);

reg sa, sb;

always_comb

        sa = au.sign;

always_comb

        sb = bu.sign;

wire az = ~|{au.exp,au.sig};

wire bz = ~|{bu.exp,bu.sig};

wire unordered = au.nan | bu.nan;

wire eq = !unordered & ((az & bz) || (a==b));  // special test for zero

wire gt1 = {au.exp,au.sig} > {bu.exp,bu.sig};

wire lt1 = {au.exp,au.sig} < {bu.exp,bu.sig};

wire lt = sa ^ sb ? sa & !(az & bz): sa ? gt1 : lt1;

always_comb

begin

        o[0] = eq;

        o[1] = lt;

        o[2] = lt|eq;

        o[3] = lt1;

        o[4] = unordered;

        o[5] = ~eq;

        o[6] = ~lt;

        o[7] = ~(lt|eq);

        o[8] = ~lt1;

        o[9] = ~unordered;

        o[10] = 1'b0;

        o[11] = lt;

end

// an unorder comparison will signal a nan exception

//assign nanx = op!=`FCOR && op!=`FCUN && unordered;

endmodule