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////  8051 alu carry select module                                ////

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////  This file is part of the 8051 cores project                 ////

////  http://www.opencores.org/cores/8051/                        ////

////                                                              ////

////  Description                                                 ////

////   Multiplexer wiht whitch we select carry in alu             ////

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////  To Do:                                                      ////

////   nothing                                                    ////

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

////      - Simon Teran, simont@opencores.org                     ////

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//// 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                     ////

////                                                              ////

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//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

// Revision 1.2  2002/09/30 17:33:59  simont

// prepared header

//

//

// synopsys translate_off

`include "oc8051_timescale.v"

// synopsys translate_on

`include "oc8051_defines.v"

module oc8051_cy_select (cy_sel, cy_in, data_in, data_out);

//

// cy_sel       (in)  carry select, from decoder (see defines.v) [oc8051_decoder.cy_sel -r]

// cy_in        (in)  carry input [oc8051_psw.data_out[7] ]

// data_in      (in)  ram data input [oc8051_ram_sel.bit_out]

// data_out     (out) data output [oc8051_alu.srcCy]

//

input [1:0] cy_sel;

input cy_in, data_in;

output data_out;

reg data_out;

always @(cy_sel or cy_in or data_in)

begin

  case (cy_sel)

    `OC8051_CY_0: data_out = 1'b0;

    `OC8051_CY_PSW: data_out = cy_in;

    `OC8051_CY_RAM: data_out = data_in;

    `OC8051_CY_1: data_out = 1'b1;

    default: data_out = 1'bx;

  endcase

end

endmodule