Subversion Repositories or1200_hp

//////////////////////////////////////////////////////////////////////

////                                                              ////

////  OR1200's Write-back Mux                                     ////

////                                                              ////

////  This file is part of the OpenRISC 1200 project              ////

////  http://www.opencores.org/cores/or1k/                        ////

////                                                              ////

////  Description                                                 ////

////  CPU's write-back stage of the pipeline                      ////

////                                                              ////

////  To Do:                                                      ////

////   - make it smaller and faster                               ////

////                                                              ////

////  Author(s):                                                  ////

////      - Damjan Lampret, lampret@opencores.org                 ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source is distributed in the hope that it will be       ////

//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////

//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////

//// PURPOSE.  See the GNU Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

// Revision 1.2  2002/03/29 15:16:56  lampret

// Some of the warnings fixed.

//

// Revision 1.1  2002/01/03 08:16:15  lampret

// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.

//

// Revision 1.8  2001/10/21 17:57:16  lampret

// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.

//

// Revision 1.7  2001/10/14 13:12:10  lampret

// MP3 version.

//

// Revision 1.1.1.1  2001/10/06 10:18:36  igorm

// no message

//

// Revision 1.2  2001/08/09 13:39:33  lampret

// Major clean-up.

//

// Revision 1.1  2001/07/20 00:46:23  lampret

// Development version of RTL. Libraries are missing.

//

//

// synopsys translate_off

`include "timescale.v"

// synopsys translate_on

`include "or1200_defines.v"

module or1200_wbmux_cm4(

                clk_i_cml_1,

                clk_i_cml_2,

                clk_i_cml_3,

        // Clock and reset

        clk, rst,

        // Internal i/f

        wb_freeze, rfwb_op,

        muxin_a, muxin_b, muxin_c, muxin_d,

        muxout, muxreg, muxreg_valid

);

input clk_i_cml_1;

input clk_i_cml_2;

input clk_i_cml_3;

reg  wb_freeze_cml_3;

reg [ 3 - 1 : 0 ] rfwb_op_cml_3;

reg [ 3 - 1 : 0 ] rfwb_op_cml_2;

reg [ 3 - 1 : 0 ] rfwb_op_cml_1;

reg [ 32 - 1 : 0 ] muxin_a_cml_2;

reg [ 32 - 1 : 0 ] muxin_d_cml_2;

reg [ 32 - 1 : 0 ] muxout_cml_3;

reg [ 32 - 1 : 0 ] muxreg_cml_3;

reg [ 32 - 1 : 0 ] muxreg_cml_2;

reg [ 32 - 1 : 0 ] muxreg_cml_1;

reg  muxreg_valid_cml_3;

reg  muxreg_valid_cml_2;

reg  muxreg_valid_cml_1;

parameter width = `OR1200_OPERAND_WIDTH;

//

// I/O

//

//

// Clock and reset

//

input                           clk;

input                           rst;

//

// Internal i/f

//

input                           wb_freeze;

input   [`OR1200_RFWBOP_WIDTH-1:0]       rfwb_op;

input   [width-1:0]              muxin_a;

input   [width-1:0]              muxin_b;

input   [width-1:0]              muxin_c;

input   [width-1:0]              muxin_d;

output  [width-1:0]              muxout;

output  [width-1:0]              muxreg;

output                          muxreg_valid;

//

// Internal wires and regs

//

reg     [width-1:0]              muxout;

reg     [width-1:0]              muxreg;

reg                             muxreg_valid;

//

// Registered output from the write-back multiplexer

//

// SynEDA CoreMultiplier

// assignment(s): muxreg, muxreg_valid

// replace(s): wb_freeze, muxout, muxreg, rfwb_op, muxreg_valid

always @(posedge clk or posedge rst) begin

        if (rst) begin

                muxreg <= #1 32'd0;

                muxreg_valid <= #1 1'b0;

        end

        else begin  muxreg_valid <= muxreg_valid_cml_3; muxreg <= muxreg_cml_3; if (!wb_freeze_cml_3) begin

                muxreg <= #1 muxout_cml_3;

                muxreg_valid <= #1 rfwb_op_cml_3[0];

        end end

end

//

// Write-back multiplexer

//

// SynEDA CoreMultiplier

// assignment(s): muxout

// replace(s): rfwb_op, muxin_a, muxin_d

always @(muxin_a_cml_2 or muxin_b or muxin_c or muxin_d_cml_2 or rfwb_op_cml_2) begin

`ifdef OR1200_ADDITIONAL_SYNOPSYS_DIRECTIVES

        case(rfwb_op_cml_2[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case infer_mux

`else

        case(rfwb_op_cml_2[`OR1200_RFWBOP_WIDTH-1:1]) // synopsys parallel_case

`endif

                2'b00: muxout = muxin_a_cml_2;

                2'b01: begin

                        muxout = muxin_b;

`ifdef OR1200_VERBOSE

// synopsys translate_off

                        $display("  WBMUX: muxin_b %h", muxin_b);

// synopsys translate_on

`endif

                end

                2'b10: begin

                        muxout = muxin_c;

`ifdef OR1200_VERBOSE

// synopsys translate_off

                        $display("  WBMUX: muxin_c %h", muxin_c);

// synopsys translate_on

`endif

                end

                2'b11: begin

                        muxout = muxin_d_cml_2 + 32'h8;

`ifdef OR1200_VERBOSE

// synopsys translate_off

                        $display("  WBMUX: muxin_d %h", muxin_d + 4'h8);

// synopsys translate_on

`endif

                end

        endcase

end

always @ (posedge clk_i_cml_1) begin

rfwb_op_cml_1 <= rfwb_op;

muxreg_cml_1 <= muxreg;

muxreg_valid_cml_1 <= muxreg_valid;

end

always @ (posedge clk_i_cml_2) begin

rfwb_op_cml_2 <= rfwb_op_cml_1;

muxin_a_cml_2 <= muxin_a;

muxin_d_cml_2 <= muxin_d;

muxreg_cml_2 <= muxreg_cml_1;

muxreg_valid_cml_2 <= muxreg_valid_cml_1;

end

always @ (posedge clk_i_cml_3) begin

wb_freeze_cml_3 <= wb_freeze;

rfwb_op_cml_3 <= rfwb_op_cml_2;

muxout_cml_3 <= muxout;

muxreg_cml_3 <= muxreg_cml_2;

muxreg_valid_cml_3 <= muxreg_valid_cml_2;

end

endmodule