at_ctr3.v
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/**************************************************************************
* *
* Copyright (C) 1994, Silicon Graphics, Inc. *
* *
* These coded instructions, statements, and computer programs contain *
* unpublished proprietary information of Silicon Graphics, Inc., and *
* are protected by Federal copyright law. They may not be disclosed *
* to third parties or copied or duplicated in any form, in whole or *
* in part, without the prior written consent of Silicon Graphics, Inc. *
* *
*************************************************************************/
// $Id: at_ctr3.v,v 1.1.1.1 2002/05/17 06:14:57 blythe Exp $
////////////////////////////////////////////////////////////////////////
//
// Project Reality
//
// module: at_ctr3
// description: Counter for attribute buffers.
//
// designer: Phil Gossett
// date: 9/6/94
//
////////////////////////////////////////////////////////////////////////
module at_ctr3 (clk, rst, enb, z);
input clk;
input rst;
input enb;
output [1:0] z;
reg [1:0] z;
// counter
always @(posedge clk or posedge rst)
begin
if (rst == 1'b1)
z <= 2'b10; // -1
else
z <= enb ? {z[0],(z == 2'b00)} : z;
end
endmodule // at_ctr3