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[/] [ft816float/] [trunk/] [rtl/] [verilog2/] [fpCompare.sv] - Blame information for rev 84

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// ============================================================================
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//        __
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//   \\__/ o\    (C) 2007-2020  Robert Finch, Waterloo
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//    \  __ /    All rights reserved.
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//     \/_//     robfinch@finitron.ca
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//       ||
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//
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//      fpCompare.sv
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//    - floating point comparison unit
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//    - parameterized width
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//    - IEEE 754 representation
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//
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//
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// This source file is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This source file is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program.  If not, see .
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//
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// ============================================================================
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import fp::*;
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module fpCompare(a, b, o, nan, snan);
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input [FPWID-1:0] a, b;
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output [4:0] o;
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reg [4:0] o;
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output nan;
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output snan;
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// Decompose the operands
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wire sa;
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wire sb;
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wire [EMSB:0] xa;
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wire [EMSB:0] xb;
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wire [FMSB:0] ma;
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wire [FMSB:0] mb;
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wire az, bz;
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wire nan_a, nan_b;
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fpDecomp u1(.i(a), .sgn(sa), .exp(xa), .man(ma), .vz(az), .qnan(), .snan(), .nan(nan_a) );
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fpDecomp u2(.i(b), .sgn(sb), .exp(xb), .man(mb), .vz(bz), .qnan(), .snan(), .nan(nan_b) );
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wire unordered = nan_a | nan_b;
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wire eq = !unordered & ((az & bz) || (a==b));  // special test for zero
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wire gt1 = {xa,ma} > {xb,mb};
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wire lt1 = {xa,ma} < {xb,mb};
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wire lt = sa ^ sb ? sa & !(az & bz): sa ? gt1 : lt1;
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always @(unordered or eq or lt or lt1)
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begin
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        o[0] = eq;
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        o[1] = lt;
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        o[2] = lt|eq;
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        o[3] = lt1;
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        o[4] = unordered;
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end
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// an unorder comparison will signal a nan exception
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//assign nanx = op!=`FCOR && op!=`FCUN && unordered;
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assign nan = nan_a|nan_b;
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assign snan = (nan_a & ~ma[FMSB]) | (nan_b & ~mb[FMSB]);
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endmodule

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