| 1 |
2 |
dinesha |
//////////////////////////////////////////////////////////////////////
|
| 2 |
|
|
//// ////
|
| 3 |
|
|
//// 8051 alu carry select module ////
|
| 4 |
|
|
//// ////
|
| 5 |
|
|
//// This file is part of the 8051 cores project ////
|
| 6 |
|
|
//// http://www.opencores.org/cores/8051/ ////
|
| 7 |
|
|
//// ////
|
| 8 |
|
|
//// Description ////
|
| 9 |
|
|
//// Multiplexer wiht whitch we select carry in alu ////
|
| 10 |
|
|
//// ////
|
| 11 |
|
|
//// To Do: ////
|
| 12 |
|
|
//// nothing ////
|
| 13 |
|
|
//// ////
|
| 14 |
|
|
//// Author(s): ////
|
| 15 |
|
|
//// - Simon Teran, simont@opencores.org ////
|
| 16 |
|
|
//// ////
|
| 17 |
|
|
//////////////////////////////////////////////////////////////////////
|
| 18 |
|
|
//// ////
|
| 19 |
|
|
//// Copyright (C) 2000 Authors and OPENCORES.ORG ////
|
| 20 |
|
|
//// ////
|
| 21 |
|
|
//// This source file may be used and distributed without ////
|
| 22 |
|
|
//// restriction provided that this copyright statement is not ////
|
| 23 |
|
|
//// removed from the file and that any derivative work contains ////
|
| 24 |
|
|
//// the original copyright notice and the associated disclaimer. ////
|
| 25 |
|
|
//// ////
|
| 26 |
|
|
//// This source file is free software; you can redistribute it ////
|
| 27 |
|
|
//// and/or modify it under the terms of the GNU Lesser General ////
|
| 28 |
|
|
//// Public License as published by the Free Software Foundation; ////
|
| 29 |
|
|
//// either version 2.1 of the License, or (at your option) any ////
|
| 30 |
|
|
//// later version. ////
|
| 31 |
|
|
//// ////
|
| 32 |
|
|
//// This source is distributed in the hope that it will be ////
|
| 33 |
|
|
//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
|
| 34 |
|
|
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
|
| 35 |
|
|
//// PURPOSE. See the GNU Lesser General Public License for more ////
|
| 36 |
|
|
//// details. ////
|
| 37 |
|
|
//// ////
|
| 38 |
|
|
//// You should have received a copy of the GNU Lesser General ////
|
| 39 |
|
|
//// Public License along with this source; if not, download it ////
|
| 40 |
|
|
//// from http://www.opencores.org/lgpl.shtml ////
|
| 41 |
|
|
//// ////
|
| 42 |
|
|
//////////////////////////////////////////////////////////////////////
|
| 43 |
|
|
//
|
| 44 |
|
|
// CVS Revision History
|
| 45 |
|
|
//
|
| 46 |
|
|
// $Log: not supported by cvs2svn $
|
| 47 |
|
|
// Revision 1.3 2003/04/02 11:26:21 simont
|
| 48 |
|
|
// updating...
|
| 49 |
|
|
//
|
| 50 |
|
|
// Revision 1.2 2002/09/30 17:33:59 simont
|
| 51 |
|
|
// prepared header
|
| 52 |
|
|
//
|
| 53 |
|
|
//
|
| 54 |
|
|
|
| 55 |
|
|
// synopsys translate_off
|
| 56 |
|
|
`include "oc8051_timescale.v"
|
| 57 |
|
|
// synopsys translate_on
|
| 58 |
|
|
|
| 59 |
|
|
`include "oc8051_defines.v"
|
| 60 |
|
|
|
| 61 |
|
|
|
| 62 |
|
|
module oc8051_cy_select (cy_sel, cy_in, data_in, data_out);
|
| 63 |
|
|
//
|
| 64 |
|
|
// cy_sel (in) carry select, from decoder (see defines.v) [oc8051_decoder.cy_sel -r]
|
| 65 |
|
|
// cy_in (in) carry input [oc8051_psw.data_out[7] ]
|
| 66 |
|
|
// data_in (in) ram data input [oc8051_ram_sel.bit_out]
|
| 67 |
|
|
// data_out (out) data output [oc8051_alu.srcCy]
|
| 68 |
|
|
//
|
| 69 |
|
|
|
| 70 |
|
|
input [1:0] cy_sel;
|
| 71 |
|
|
input cy_in, data_in;
|
| 72 |
|
|
|
| 73 |
|
|
output data_out;
|
| 74 |
|
|
reg data_out;
|
| 75 |
|
|
|
| 76 |
|
|
always @(cy_sel or cy_in or data_in)
|
| 77 |
|
|
begin
|
| 78 |
|
|
case (cy_sel) /* synopsys full_case parallel_case */
|
| 79 |
|
|
`OC8051_CY_0: data_out = 1'b0;
|
| 80 |
|
|
`OC8051_CY_PSW: data_out = cy_in;
|
| 81 |
|
|
`OC8051_CY_RAM: data_out = data_in;
|
| 82 |
|
|
`OC8051_CY_1: data_out = 1'b1;
|
| 83 |
|
|
endcase
|
| 84 |
|
|
end
|
| 85 |
|
|
|
| 86 |
|
|
endmodule
|
