mod_time = rem((t - timeRange(2))/timeRange(1), 1)...
      * timeRange(1) + timeRange(2);
  last_time = x(3);
  x(3) = mod_time;
  
  if (mod_time < last_time)
    if storeLength <= 0
      storeLength = 1;
    end
    %hit the boundary of switching point.
    pre_point = mod_time + timeRange(1);
    aft_point = mod_time;
    ind = [];
    if sub_han(len_u+2) >= storeLength
      ind = find( isnan( sub_han( len_u + 3:length(sub_han) ) ) );
      sub_han(len_u+3:ind(max(1, length(ind)-storeLength))) = [];
      sub_han(len_u+2) = sum( isnan( sub_han( len_u + 3:length(sub_han) ) ) );
    end;
    
    sub_han(len_u + 2) = sub_han(len_u + 2) + 1;
    sub_han = [sub_han   t   NaN   t];
    set(handles(1),'UserData',sub_han);
    
    for i = 1 : len_u
      if sub_han(i) 
	tmp_x = get(sub_han(i), 'XData');
	tmp_y = get(sub_han(i), 'YData');
	if ~isempty(ind)
	  tmp_x(1:ind(max(1, length(ind)-storeLength))-len_u-2) = [];
	  tmp_y(1:ind(max(1, length(ind)-storeLength))-len_u-2) = [];
	end;
	set(sub_han(i), 'XData',[tmp_x, pre_point, NaN, aft_point],...
	    'YData',[tmp_y, u(i),      NaN, u(i)]);
      end;
    end;
    
  else
    set(handles(1), 'UserData',[get(handles(1), 'UserData') t])
    for i = 1 : len_u
      if sub_han(i)
	set(sub_han(i), 'XData', [get(sub_han(i), 'XData'), mod_time], ...
	    'YData', [get(sub_han(i), 'YData'), u(i)]);
      end;
    end;
  end;
  
  if triggered & sub_han(len_u) & (t > 0)
    if storeLength <= 0
      storeLength = 1;
    end
    tmp_x = get(sub_han(len_u + 1), 'XData');
    tmp_y = get(sub_han(len_u + 1), 'YData');
    if length(tmp_x) > 3*storeLength
      tmp_x(1:3) = [];
      tmp_y(1:3) = [];
    end;
    tmp_x = [timeRange(3), timeRange(3)];
    tmp_y = [get(handles(1), 'YLim')];
    set(sub_han(len_u + 1), 'XData', tmp_x, 'YData', tmp_y);
  end;
end;

if handles(2) & triggered & (t>0) & scatter_plot
  if storeLength <= 0
    storeLength = 1;
  end    
  
  %scatter plot
  sub_han = get(handles(2), 'UserData');
  if changed_boundary
    set(handles(2), 'Ylim', boundary);
    if len_u == 2
      set(handles(2), 'Xlim', boundary);
    end;
  end;
  
  len_h_userdata = length(sub_han);
  changed_line_type = 0;
  if (length(scatterLine) ~= len_h_userdata - len_u)
    changed_line_type = 1;
  elseif max(abs(scatterLine) ~= sub_han(len_u+1:len_h_userdata))
    changed_line_type = 1;
  end;
  
  if changed_line_type
    lines = scatterLine;
    for i = 1 : len_u
      [col, lines] = strtok(lines, '/');
      if length(col) <= 1
	col = 'k-';
      end;
      if ~((i == 2) & (len_u == 2))
	[linest, markst] = LineTypeSeparation(col(2:length(col)));
	set(sub_han(i), 'Color',col(1),...
	    'LineStyle',linest,...
	    'Marker', markst);
	if col(2) == '.'
	  set(sub_han(i), 'MarkerSize', 10);
	else
	  set(sub_han(i), 'MarkerSize', 6);
	end;
      end;
    end;
    set(handles(2), 'UserData',[sub_han(1:len_u), abs(scatterLine)]);
  end;
  
  if len_u == 2
    tmp_x = get(sub_han(1), 'XData');
    tmp_y = get(sub_han(1), 'YData');
    if length(tmp_x) > 2*storeLength
      tmp_x(1:2) = [];
      tmp_y(1:2) = [];
    end;
    tmp_x = [tmp_x, u(1), NaN];
    tmp_y = [tmp_y, u(2), NaN];
    set(sub_han(1), 'XData', tmp_x, 'YData', tmp_y);
  else
    for i = 1 : len_u
      tmp_x = get(sub_han(i), 'XData');
      tmp_y = get(sub_han(i), 'YData');
      if length(tmp_x) > 2*storeLength
	tmp_x(1:2) = [];
	tmp_y(1:2) = [];
      end;
      tmp_x = [tmp_x, 0, NaN];
      tmp_y = [tmp_y, u(i), NaN];
      set(sub_han(i), 'XData', tmp_x, 'YData', tmp_y);
    end;
  end;
end;
  
sys = x;

% end mdlUpdate

%
%=============================================================================
% LocalFigureDeleteFcn
% This is the Graph figure window's DeleteFcn.  The figure window is
% being deleted, update the Graph block's UserData to reflect the change.
%=============================================================================
%
function LocalFigureDeleteFcn

%
% Get the block associated with this figure and set it's figure to -1
%
SetEyesamplFigure(gcbh, get_param(gcbh,'userdata'));
close(gcbf);

% end LocalFigureDeleteFcn

%
%=============================================================================
% LocalBlockStartFcn
% Function that is called when the simulation starts.  Initialize the
% Graph scope figure.
%=============================================================================
%
function LocalBlockStartFcn

%
% get the figure associated with this block, create a figure if it doesn't
% exist
%
figureHandle = GetEyesamplFigure(gcbh);
if ~ishandle(figureHandle),
  figureHandle = CreateEyesamplFigure;
end

ud = get(figureHandle,'UserData');
set(figureHandle,'UserData',ud);

% end LocalBlockStartFcn

%
%=============================================================================
% LocalBlockStopFcn
% At the end of the simulation, set the line's X and Y data to contain
% the complete set of points that were acquire during the simulation.
% Recall that during the simulation, the lines are only small segments from
% the last time step to the current one.
%=============================================================================
%
function LocalBlockStopFcn

%
% Locate the figure window associated with this block. If it's not a valid
% handle (it may have been closed by the user), then return.
%
figureHandle=GetEyesamplFigure(gcbh);
if ishandle(figureHandle),
  %
  % Get UserData of the figure.
  %
  ud = get(figureHandle,'UserData');
  % Currently do nothing in LocalBlockStopFcn

end

% end LocalBlockStopFcn

%
%=============================================================================
% LocalBlockNameChangeFcn
% Function that handles name changes on the Bit-Error Meter.
%=============================================================================
%
function LocalBlockNameChangeFcn

%
% the figure handle is stored in the block's UserData
%
figureHandle = GetEyesamplFigure(gcbh);
if ishandle(figureHandle),
  set(figureHandle,'Name',get_param(gcbh,'Name'));
end

% end LocalBlockNameChangeFcn

%
%=============================================================================
% LocalBlockLoadCopyFcn
% Function that initializes the Bit-Error Meter's UserData when it is
% loaded from an mdl file and when it is copied.
%=============================================================================
%
function LocalBlockLoadCopyFcn

SetEyesamplFigure(gcbh,[]);

% end LocalBlockLoadCopyFcn

%
%=============================================================================
% LocalBlockDeleteFcn
% Function that handles the Bit-Error Meter's deletion from a block
% diagram.
%=============================================================================
%
function LocalBlockDeleteFcn

%
% the figure handle is stored in the block's UserData
%
figureHandle = GetEyesamplFigure(gcbh);
if ishandle(figureHandle),
  delete(figureHandle);
  SetEyesamplFigure(gcbh,[]);
end

% end LocalBlockDeleteFcn

%
%=============================================================================
% GetEyesamplFigure
% Retrieves the figure window associated with this S-function Bit-Error Meter
% from the block's parent subsystem's UserData.
%=============================================================================
%
function figureHandle=GetEyesamplFigure(block)

if strcmp(get_param(block,'BlockType'),'S-Function'),
  block=get_param(block,'Parent');
end

ud = get_param(block,'UserData');
if ishandle(ud)
  figureHandle = ud;
else
  if isempty(ud)
    ud.figureHandle = [];
    set_param(block,'UserData', ud);
  end;  
  figureHandle = ud.figureHandle;
end;

if isempty(figureHandle),
  figureHandle = -1;
end

% end GetEyesamplFigure

%
%=============================================================================
% SetEyesamplFigure
% Stores the figure window associated with this S-function Bit-Error Meter
% in the block's parent subsystem's UserData.
%=============================================================================
%
function SetEyesamplFigure(block,figureHandle)

if strcmp(get_param(block,'BlockType'),'S-Function'),
  block=get_param(block,'Parent');
end

ud = get_param(block,'UserData');
ud.figureHandle = figureHandle;
set_param(block,'UserData',ud);

% end SetEyesamplFigure

%
%=============================================================================
% CreateEyesamplFigure
% Creates the figure window associated with this S-function Bit-Error Meter.
%=============================================================================
%
function figureHandle=CreateEyesamplFigure

%
% create the figure and the axes
%

a = allchild(0);
b = findobj(a, 'Name', get_param(gcbh,'Name'));
if isempty(b)
   figureHandle = figure(...
      'Units',        'points',...
      'Position',     [10 10 360 350],...
      'NumberTitle',  'off',...
      'Name',         get_param(gcbh,'Name'),...
      'Visible',      'off', ...      
      'IntegerHandle','off',...
      'DeleteFcn',    'eyesampl([],[],[],''DeleteFigure'')'...
      );
else
  figureHandle = b;
end;
set(0, 'CurrentFigure', figureHandle);

%
% store the block's handle in the figure's UserData
%
ud.Block = gcbh;
%ud.figureHandle = figureHandle;

%
% squirrel the figure handle away in the current block, and put the
% various handles into the figure's UserData
%
SetEyesamplFigure(gcbh,figureHandle);
set(figureHandle,'HandleVisibility','callback','UserData',ud);

% end CreateEyesamplFigure

%
%=============================================================================
% SetBlockCallbacks
% This sets the callbacks of the block if it is not a reference.
%=============================================================================
%
function SetBlockCallbacks(block)

%
% the actual source of the block is the parent subsystem
%
block=get_param(block,'Parent');

%
% if the block isn't linked, issue a warning, and then set the callbacks
% for the block so that it has the proper operation
%
if strcmp(get_param(block,'LinkStatus'),'none'),
%  warnmsg=sprintf(['The Eye-Pattern diagram block ''%s'' should be replaced with a ' ...
%                   'new version from the com_sour block library'],...
%                   block);
%  warning(warnmsg);

  callbacks={
    'CopyFcn',       'eyesampl([],[],[],''CopyBlock'')' ;
    'DeleteFcn',     'eyesampl([],[],[],''DeleteBlock'')' ;
    'LoadFcn',       'eyesampl([],[],[],''LoadBlock'')' ;
    'StartFcn',      'eyesampl([],[],[],''Start'')' ;
    'StopFcn'        'eyesampl([],[],[],''Stop'')' ;
    'NameChangeFcn', 'eyesampl([],[],[],''NameChange'')' ;
  };

  for i=1:length(callbacks)
    if ~strcmp(get_param(block,callbacks{i,1}),callbacks{i,2})
      set_param(block,callbacks{i,1},callbacks{i,2});
    end
  end
end

% end SetBlockCallbacks

%
%===============================================================
% Local Function
% This is used to separate the line type and mark type.
%===============================================================
%
function [linest, markst] = LineTypeSeparation(linetype)

% take out the marks
linest = linetype;
linidx = [findstr(linetype, '.'), ...
          findstr(linetype, 'o'), ...
          findstr(linetype, 'x'), ...
          findstr(linetype, '+'), ...
          findstr(linetype, '*'), ...
          findstr(linetype, 's'), ...
          findstr(linetype, 'd'), ...
          findstr(linetype, 'v'), ...
          findstr(linetype, '^'), ...
          findstr(linetype, '<'), ...
          findstr(linetype, '>'), ...
          findstr(linetype, 'p'), ...
          findstr(linetype, 'h')];
markst = 'none';
if ~isempty(linidx)
  markst = linetype(linidx);
  linest(linidx) = [];
end;
if isempty(linest)
  linest = 'none';
end;

%%%%%%%%%%%%%%%%%%%%%%%%
%   End of EYESAMPL.M   %
%%%%%%%%%%%%%%%%%%%%%%%%