oc8051_cy_select.v

verilog code,about oc8051

//////////////////////////////////////////////////////////////////////
////                                                              ////
////  8051 alu carry select module                                ////
////                                                              ////
////  This file is part of the 8051 cores project                 ////
////  http://www.opencores.org/cores/8051/                        ////
////                                                              ////
////  Description                                                 ////
////   Multiplexer wiht whitch we select carry in alu             ////
////                                                              ////
////  To Do:                                                      ////
////   nothing                                                    ////
////                                                              ////
////  Author(s):                                                  ////
////      - Simon Teran, [e-mail]                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// 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: oc8051_cy_select.v,v $
// Revision 1.4  2003/07/01 20:47:38  simont
// add /* synopsys xx_case */ to case statments.
//
// Revision 1.3  2003/04/02 11:26:21  simont
// updating...
//
// 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) /* synopsys full_case parallel_case */
    `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;
  endcase
end

endmodule