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`include "Raptor64_opcodes.v"

`timescale 1ns / 1ps

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

//        __

//   \\__/ o\    (C) 2011,2012  Robert Finch

//    \  __ /    All rights reserved.

//     \/_//     robfinch<remove>@opencores.org

//       ||

//  

//      Raptor64_addsub.v

//  - addsub datapath operations

//

//  

// 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/>.    

//                                                                          

//

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

//

module Raptor64_addsub(xIR, a, b, imm, o);

input [31:0] xIR;

input [63:0] a;

input [63:0] b;

input [63:0] imm;

output [63:0] o;

reg [63:0] o;

wire [6:0] xOpcode = xIR[31:25];

wire [5:0] xFunc = xIR[5:0];

wire [7:0] bcdaddo,bcdsubo;

BCDAdd u1(.ci(1'b0),.a(a[7:0]),.b(b[7:0]),.o(bcdaddo),.c());

BCDSub u2(.ci(1'b0),.a(a[7:0]),.b(b[7:0]),.o(bcdsubo),.c());

always @(xOpcode,xFunc,a,b,imm,bcdaddo,bcdsubo)

case (xOpcode)

`RR:

        case(xFunc)

        `ADD:   o = a + b;

        `ADDU:  o = a + b;

        `SUB:   o = a - b;

        `SUBU:  o = a - b;

        `BCD_ADD:       o = bcdaddo;

        `BCD_SUB:       o = bcdsubo;

        default:        o = 64'd0;

        endcase

`INB,`INCH,`INH,`INW,`INCU,`INHU,`INBU,

`OUTB,`OUTC,`OUTH,`OUTW,`OUTBC,

`LW,`LH,`LC,`LB,`LHU,`LCU,`LBU,`LEA,`LF,`LFD,`LWR,

`SW,`SH,`SC,`SB,`SF,`SFD,`SWC,

`ADDI,`ADDUI:

                o = a + imm;

`SUBI:  o = a - imm;

`SUBUI: o = a - imm;

default:        o = 64'd0;

endcase

endmodule