// ============================================================================
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// ============================================================================
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// __
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// __
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// \\__/ o\ (C) 2020 Robert Finch, Waterloo
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// \\__/ o\ (C) 2020 Robert Finch, Waterloo
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// \ __ / All rights reserved.
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// \ __ / All rights reserved.
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// \/_// robfinch@finitron.ca
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// \/_// robfinch@finitron.ca
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// ||
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// ||
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//
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//
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// positToInt.sv
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// positToInt.sv
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// - posit number to integer convertor
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// - posit number to integer convertor
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// - can issue every clock cycle
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// - can issue every clock cycle
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// - parameterized width
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// - parameterized width
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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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// 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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// 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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// 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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// (at your option) any later version.
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//
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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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// 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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// 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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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// GNU General Public License for more details.
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//
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//
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// You should have received a copy of the GNU General Public License
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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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// along with this program. If not, see .
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//
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//
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// ============================================================================
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// ============================================================================
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`include "positConfig.sv"
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`include "positConfig.sv"
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module positToInt(i, o);
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module positToInt(i, o);
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`include "positSize.sv"
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`include "positSize.sv"
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input [PSTWID-1:0] i;
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input [PSTWID-1:0] i;
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output reg [PSTWID-1:0] o;
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output reg [PSTWID-1:0] o;
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localparam N = PSTWID;
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localparam N = PSTWID;
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localparam Bs = $clog2(PSTWID-1);
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localparam Bs = $clog2(PSTWID-1);
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wire sgn;
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wire sgn;
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wire rgs;
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wire rgs;
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wire [Bs-1:0] rgm;
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wire [Bs-1:0] rgm;
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wire [es-1:0] exp;
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wire [es-1:0] exp;
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wire [N-es-1:0] sig;
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wire [N-es-1:0] sig;
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wire zer;
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wire zer;
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wire inf;
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wire inf;
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positDecompose #(.PSTWID(PSTWID), .es(es)) u1 (.i(i), .sgn(sgn), .rgs(rgs), .rgm(rgm), .exp(exp), .sig(sig), .zer(zer), .inf(inf));
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positDecompose #(.PSTWID(PSTWID), .es(es)) u1 (.i(i), .sgn(sgn), .rgs(rgs), .rgm(rgm), .exp(exp), .sig(sig), .zer(zer), .inf(inf));
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wire [N-1:0] m = {sig,{es{1'b0}}};
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wire [N-1:0] m = {sig,{es{1'b0}}};
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// If we have a negative regime then the number is a fraction less than one (output a zero).
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wire isZero = zer;
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wire isZero = zer|~rgs;
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wire [15:0] argm = rgs ? rgm : -rgm;
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wire [15:0] ex = (rgm << es) + exp;
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wire [15:0] ex1 = (argm << es) + exp;
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wire [N-1:0] mo = m >> (PSTWID-ex-1);
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wire exv = ~ex1[15] && ex1 > PSTWID-1;
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wire [N*2-1:0] mo = {m,{N{1'b0}}} >> (PSTWID-ex1-1);
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wire L = mo[N];
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wire G = mo[N-1];
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wire R = mo[N-2];
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wire St = |mo[N-3:0];
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// If regime+exp == -1 then the value is 0.5 or greater, so round up.
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// If the regime+exp < -1 then the values is 0.25 or less, do not round up.
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// Otherwise use rounding rules.
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wire ulp = (~ex1[15] && ((G & (R | St)) | (L & G & ~(R | St)))) ||
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(ex1==16'hFFFF);
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wire [PSTWID-1:0] rnd_ulp = {{PSTWID-1{1'b0}},ulp};
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wire [PSTWID-1:0] tmp = ~rgs ? rnd_ulp : mo[N*2-1:N] + rnd_ulp;
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always @*
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always @*
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casez({isZero,inf}) // exponent all ones or exponent overflow?
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casez({isZero,inf|exv}) // exponent all ones or exponent overflow?
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// convert to +0.0 zero-in zero-out (the sign will always be plus)
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// convert to +0.0 zero-in zero-out (the sign will always be plus)
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2'b1?: o = {PSTWID{1'b0}};
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2'b1?: o = {PSTWID{1'b0}};
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// Infinity in or exponent overflow in conversion = infinity out
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// Infinity in or exponent overflow in conversion = infinity out
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2'b01: o = {1'b1,{PSTWID-1{1'b0}}};
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2'b01: o = {1'b1,{PSTWID-1{1'b0}}};
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// Other numbers
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// Other numbers
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default: o = sgn ? -mo : mo;
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default: o = sgn ? -tmp : tmp;
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endcase
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endcase
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endmodule
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endmodule
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