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[/] [s80186/] [trunk/] [rtl/] [alu/] [sar.sv] - Blame information for rev 2

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1 2 jamieiles
// Copyright Jamie Iles, 2017
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//
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// This file is part of s80x86.
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//
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// s80x86 is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// 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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// s80x86 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 s80x86.  If not, see .
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task do_sar;
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    output [31:0] out;
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    input is_8_bit;
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    input [15:0] a;
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    input [4:0] shift_count;
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    input [15:0] flags_in;
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    output [15:0] flags_out;
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    output busy;
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    input multibit_shift;
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    begin
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        flags_out = flags_in;
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        out = {11'b0, shift_count, a};
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        if (|shift_count || !multibit_shift) begin
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            if (!is_8_bit)
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                {out[15:0], flags_out[CF_IDX]} = $signed({a, 1'b0}) >>> 1'b1;
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            else
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                {out[7:0], flags_out[CF_IDX]} = $signed({a[7:0], 1'b0}) >>> 1'b1;
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            flags_out[OF_IDX] = 0;
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            shift_flags(flags_out, is_8_bit, out[15:0], a);
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            out[31:16] = {11'b0, shift_count - 1'b1};
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        end
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        busy = multibit_shift && |out[20:16];
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    end
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endtask

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