//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// ////
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//// OR1200's Write-back Mux ////
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//// OR1200's Write-back Mux ////
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//// ////
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//// ////
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//// This file is part of the OpenRISC 1200 project ////
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//// This file is part of the OpenRISC 1200 project ////
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//// http://www.opencores.org/project,or1k ////
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//// http://www.opencores.org/project,or1k ////
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//// ////
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//// ////
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//// Description ////
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//// Description ////
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//// CPU's write-back stage of the pipeline ////
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//// CPU's write-back stage of the pipeline ////
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//// ////
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//// ////
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//// To Do: ////
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//// To Do: ////
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//// - make it smaller and faster ////
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//// - make it smaller and faster ////
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//// ////
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//// ////
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//// Author(s): ////
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//// Author(s): ////
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//// - Damjan Lampret, lampret@opencores.org ////
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//// - Damjan Lampret, lampret@opencores.org ////
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//// ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// ////
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//// Copyright (C) 2000 Authors and OPENCORES.ORG ////
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//// Copyright (C) 2000 Authors and OPENCORES.ORG ////
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//// ////
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//// ////
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//// This source file may be used and distributed without ////
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//// This source file may be used and distributed without ////
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//// restriction provided that this copyright statement is not ////
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//// restriction provided that this copyright statement is not ////
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//// removed from the file and that any derivative work contains ////
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//// removed from the file and that any derivative work contains ////
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//// the original copyright notice and the associated disclaimer. ////
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//// the original copyright notice and the associated disclaimer. ////
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//// ////
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//// ////
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//// This source file is free software; you can redistribute it ////
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//// This source file is free software; you can redistribute it ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// Public License as published by the Free Software Foundation; ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// later version. ////
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//// later version. ////
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//// ////
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//// ////
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//// This source is distributed in the hope that it will be ////
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//// This source is distributed in the hope that it will be ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// details. ////
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//// details. ////
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//// ////
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//// ////
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//// You should have received a copy of the GNU Lesser General ////
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//// You should have received a copy of the GNU Lesser General ////
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//// Public License along with this source; if not, download it ////
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//// Public License along with this source; if not, download it ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//
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//
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//
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//
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// $Log: or1200_wbmux.v,v $
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// $Log: or1200_wbmux.v,v $
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// Revision 2.0 2010/06/30 11:00:00 ORSoC
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// Revision 2.0 2010/06/30 11:00:00 ORSoC
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// No update
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// No update
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// synopsys translate_off
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// synopsys translate_off
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`include "timescale.v"
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`include "timescale.v"
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// synopsys translate_on
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// synopsys translate_on
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`include "or1200_defines.v"
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`include "or1200_defines.v"
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module or1200_wbmux(
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module or1200_wbmux(
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// Clock and reset
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// Clock and reset
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clk, rst,
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clk, rst,
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// Internal i/f
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// Internal i/f
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wb_freeze, rfwb_op,
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wb_freeze, rfwb_op,
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muxin_a, muxin_b, muxin_c, muxin_d, muxin_e,
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muxin_a, muxin_b, muxin_c, muxin_d, muxin_e,
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muxout, muxreg, muxreg_valid
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muxout, muxreg, muxreg_valid
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);
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);
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parameter width = `OR1200_OPERAND_WIDTH;
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parameter width = `OR1200_OPERAND_WIDTH;
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//
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//
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// I/O
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// I/O
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//
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//
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//
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//
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// Clock and reset
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// Clock and reset
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//
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//
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input clk;
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input clk;
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input rst;
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input rst;
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//
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//
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// Internal i/f
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// Internal i/f
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//
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//
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input wb_freeze;
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input wb_freeze;
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input [`OR1200_RFWBOP_WIDTH-1:0] rfwb_op;
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input [`OR1200_RFWBOP_WIDTH-1:0] rfwb_op;
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input [width-1:0] muxin_a;
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input [width-1:0] muxin_a;
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input [width-1:0] muxin_b;
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input [width-1:0] muxin_b;
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input [width-1:0] muxin_c;
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input [width-1:0] muxin_c;
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input [width-1:0] muxin_d;
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input [width-1:0] muxin_d;
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input [width-1:0] muxin_e;
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input [width-1:0] muxin_e;
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output [width-1:0] muxout;
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output [width-1:0] muxout;
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output [width-1:0] muxreg;
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output [width-1:0] muxreg;
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output muxreg_valid;
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output muxreg_valid;
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//
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//
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// Internal wires and regs
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// Internal wires and regs
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//
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//
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reg [width-1:0] muxout;
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reg [width-1:0] muxout;
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reg [width-1:0] muxreg;
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reg [width-1:0] muxreg;
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reg muxreg_valid;
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reg muxreg_valid;
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//
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//
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// Registered output from the write-back multiplexer
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// Registered output from the write-back multiplexer
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//
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//
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always @(posedge clk or `OR1200_RST_EVENT rst) begin
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always @(posedge clk or `OR1200_RST_EVENT rst) begin
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if (rst == `OR1200_RST_VALUE) begin
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if (rst == `OR1200_RST_VALUE) begin
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muxreg <= 32'd0;
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muxreg <= 32'd0;
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muxreg_valid <= 1'b0;
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muxreg_valid <= 1'b0;
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end
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end
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else if (!wb_freeze) begin
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else if (!wb_freeze) begin
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muxreg <= muxout;
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muxreg <= muxout;
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muxreg_valid <= rfwb_op[0];
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muxreg_valid <= rfwb_op[0];
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end
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end
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end
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end
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//
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//
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// Write-back multiplexer
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// Write-back multiplexer
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//
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//
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always @(muxin_a or muxin_b or muxin_c or muxin_d or muxin_e or rfwb_op) begin
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always @(muxin_a or muxin_b or muxin_c or muxin_d or muxin_e or rfwb_op) begin
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`ifdef OR1200_ADDITIONAL_SYNOPSYS_DIRECTIVES
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`ifdef OR1200_ADDITIONAL_SYNOPSYS_DIRECTIVES
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case(rfwb_op[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case infer_mux
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casez(rfwb_op[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case infer_mux
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`else
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`else
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case(rfwb_op[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case
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casez(rfwb_op[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case
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`endif
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`endif
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`OR1200_RFWBOP_ALU: muxout = muxin_a;
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`OR1200_RFWBOP_ALU: muxout = muxin_a;
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`OR1200_RFWBOP_LSU: begin
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`OR1200_RFWBOP_LSU: begin
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muxout = muxin_b;
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muxout = muxin_b;
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`ifdef OR1200_VERBOSE
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`ifdef OR1200_VERBOSE
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// synopsys translate_off
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// synopsys translate_off
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$display(" WBMUX: muxin_b %h", muxin_b);
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$display(" WBMUX: muxin_b %h", muxin_b);
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// synopsys translate_on
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// synopsys translate_on
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`endif
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`endif
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end
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end
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`OR1200_RFWBOP_SPRS: begin
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`OR1200_RFWBOP_SPRS: begin
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muxout = muxin_c;
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muxout = muxin_c;
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`ifdef OR1200_VERBOSE
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`ifdef OR1200_VERBOSE
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// synopsys translate_off
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// synopsys translate_off
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$display(" WBMUX: muxin_c %h", muxin_c);
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$display(" WBMUX: muxin_c %h", muxin_c);
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// synopsys translate_on
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// synopsys translate_on
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`endif
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`endif
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end
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end
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`OR1200_RFWBOP_LR: begin
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`OR1200_RFWBOP_LR: begin
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muxout = muxin_d + 32'h8;
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muxout = muxin_d + 32'h8;
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`ifdef OR1200_VERBOSE
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`ifdef OR1200_VERBOSE
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// synopsys translate_off
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// synopsys translate_off
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$display(" WBMUX: muxin_d %h", muxin_d + 4'h8);
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$display(" WBMUX: muxin_d %h", muxin_d + 4'h8);
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// synopsys translate_on
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// synopsys translate_on
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`endif
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`endif
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end
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end
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`ifdef OR1200_FPU_IMPLEMENTED
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`ifdef OR1200_FPU_IMPLEMENTED
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`OR1200_RFWBOP_FPU : begin
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`OR1200_RFWBOP_FPU : begin
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muxout = muxin_e;
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muxout = muxin_e;
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`ifdef OR1200_VERBOSE
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`ifdef OR1200_VERBOSE
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// synopsys translate_off
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// synopsys translate_off
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$display(" WBMUX: muxin_e %h", muxin_e);
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$display(" WBMUX: muxin_e %h", muxin_e);
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// synopsys translate_on
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// synopsys translate_on
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`endif
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`endif
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end
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end
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`endif
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`endif
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default : begin
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muxout = 0;
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end
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endcase
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endcase
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end
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end
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endmodule
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endmodule
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