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[/] [thor/] [trunk/] [FT64/] [rtl/] [common/] [FT64_shifth.v] - Blame information for rev 43

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1 43 robfinch
`timescale 1ns / 1ps
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// ============================================================================
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//        __
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//   \\__/ o\    (C) 2016-2018  Robert Finch, Waterloo
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//    \  __ /    All rights reserved.
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//     \/_//     robfinch<remove>@finitron.ca
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//       ||
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//
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//      FT64_shifth.v
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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 <http://www.gnu.org/licenses/>.    
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//                                                                          
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//
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// ============================================================================
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//
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//`ifndef SHL
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`define RR      6'h02
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`define AMO             6'h2F
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`define AMOSHL          6'h0C
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`define AMOSHR          6'h0D
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`define AMOASR          6'h0E
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`define AMOROL          6'h0F
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`define AMOSHLI         6'h2C
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`define AMOSHRI         6'h2D
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`define AMOASRI         6'h2E
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`define AMOROLI         6'h2F
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`define SHIFTH  6'h3F
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`define SHL     4'h0
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`define SHR     4'h1
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`define ASL     4'h2
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`define ASR     4'h3
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`define ROL     4'h4
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`define ROR     4'h5
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`define SHLI    4'h8
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`define SHRI    4'h9
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`define ASLI    4'hA
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`define ASRI    4'hB
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`define ROLI    4'hC
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`define RORI    4'hD
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//`endif
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`define HIGHWORDH    63:32
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module FT64_shifth(instr, a, b, res, ov);
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parameter DMSB=31;
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input [31:0] instr;
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input [DMSB:0] a;
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input [DMSB:0] b;
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output [DMSB:0] res;
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reg [DMSB:0] res;
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output ov;
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parameter ROTATE_INSN = 1;
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wire [5:0] opcode = instr[5:0];
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wire [5:0] func = instr[31:26];
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wire [3:0] shiftop = instr[25:22];
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wire [63:0] shl = {32'd0,a} << b[4:0];
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wire [63:0] shr = {a,32'd0} >> b[4:0];
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assign ov = 1'b0;
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always @*
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case(opcode)
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`RR:
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    case(func)
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    `SHIFTH:
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        case(shiftop)
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        `SHLI,`ASLI:    res <= shl[DMSB:0];
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        `SHL,`ASL:      res <= shl[DMSB:0];
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        `SHRI:  res <= shr[`HIGHWORDH];
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        `SHR:   res <= shr[`HIGHWORDH];
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        `ASRI:  if (a[DMSB])
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                    res <= (shr[`HIGHWORDH]) | ~({32{1'b1}} >> b[4:0]);
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                else
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                    res <= shr[`HIGHWORDH];
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        `ASR:   if (a[DMSB])
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                    res <= (shr[`HIGHWORDH]) | ~({32{1'b1}} >> b[4:0]);
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                else
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                    res <= shr[`HIGHWORDH];
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        `ROL:   res <= ROTATE_INSN ? shl[DMSB:0]|shl[`HIGHWORDH] : 32'hDEADDEAD;
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        `ROLI:  res <= ROTATE_INSN ? shl[DMSB:0]|shl[`HIGHWORDH] : 32'hDEADDEAD;
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        `ROR:   res <= ROTATE_INSN ? shr[DMSB:0]|shr[`HIGHWORDH] : 32'hDEADDEAD;
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        `RORI:  res <= ROTATE_INSN ? shr[DMSB:0]|shr[`HIGHWORDH] : 32'hDEADDEAD;
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        default: res <= 32'd0;
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        endcase
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    default:    res <= 32'd0;
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    endcase
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`AMO:
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        case(func)
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        `AMOSHL,`AMOSHLI:       res <= shl[DMSB:0];
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        `AMOSHR,`AMOSHRI:       res <= shr[`HIGHWORDH];
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        `AMOASR,`AMOASRI:       if (a[DMSB])
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                                res <= (shr[`HIGHWORDH]) | ~({32{1'b1}} >> b[4:0]);
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                                else
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                                res <= shr[`HIGHWORDH];
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    `AMOROL:    res <= ROTATE_INSN ? shl[DMSB:0]|shl[`HIGHWORDH] : 32'hDEADDEAD;
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    `AMOROLI:   res <= ROTATE_INSN ? shl[DMSB:0]|shl[`HIGHWORDH] : 32'hDEADDEAD;
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        default:        res <= 32'd0;
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        endcase
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default:        res <= 32'd0;
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endcase
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endmodule
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