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// ============================================================================

//        __

//   \\__/ o\    (C) 2013  Robert Finch, Stratford

//    \  __ /    All rights reserved.

//     \/_//     robfinch<remove>@finitron.ca

//       ||

//

// 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 3 of the License, or     

// (at your option) any later version.                                      

//                                                                          

// This source file 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 General Public License for more details.                             

//                                                                          

// You should have received a copy of the GNU General Public License        

// along with this program.  If not, see <http://www.gnu.org/licenses/>.    

//

//

// Thor SuperScalar

// Shift logic

//

// ============================================================================

//

`include "Thor_defines.v"

module Thor_shifter(func, a, b, o);

parameter DBW=64;

input [5:0] func;

input [DBW-1:0] a;

input [DBW-1:0] b;

output reg [DBW-1:0] o;

wire [DBW*2-1:0] shlo = {{DBW{1'd0}},a} << b[5:0];

wire [DBW*2-1:0] shruo = {a,{DBW{1'b0}}} >> b[5:0];

wire signed [DBW-1:0] as = a;

wire signed [DBW-1:0] shro = as >> b[5:0];

always @(func or shlo or shro or shruo)

case(func)

`SHL,`SHLU,`SHLI,`SHLUI:

        o <= shlo[DBW-1:0];

`SHR,`SHRI:

        o <= shro;

`SHRU,`SHRUI:

        o <= shruo[DBW*2-1:DBW];

`ROL,`ROLI:

        o <= shlo[DBW*2-1:DBW]|shlo[DBW-1:0];

`ROR,`RORI:

        o <= shruo[DBW*2-1:DBW]|shruo[DBW-1:0];

default:        o <= 64'hDEADDEADDEADDEAD;

endcase

endmodule