function [sys,x0,str,ts]=zhe13(t,x,u,flag)
switch flag,

  %%%%%%%%%%%%%%%%%%
  % Initialization %
  %%%%%%%%%%%%%%%%%%
  case 0,
    [sys,x0,str,ts]=mdlInitializeSizes;

  %%%%%%%%%%%%%%%
  % Derivatives %
  %%%%%%%%%%%%%%%
  case 1,
    sys=[];

  %%%%%%%%%%
  % Update %
  %%%%%%%%%%
  case 2,
    sys=mdlUpdate(t,x,u);

  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  case 3,
    sys=mdlOutputs(t,x,u);

  %%%%%%%%%%%%%%%%%%%%%%%
  % GetTimeOfNextVarHit %
  %%%%%%%%%%%%%%%%%%%%%%%
  case 4,
    sys=[];

  %%%%%%%%%%%%%
  % Terminate %
  %%%%%%%%%%%%%
  case 9,
    sys=mdlTerminate(t,x,u);

  %%%%%%%%%%%%%%%%%%%%
  % Unexpected flags %
  %%%%%%%%%%%%%%%%%%%%
  otherwise
    error(['Unhandled flag = ',num2str(flag)]);

end

% end sfuntmpl

%
%=============================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=============================================================================
%
function [sys,x0,str,ts]=mdlInitializeSizes

%
% call simsizes for a sizes structure, fill it in and convert it to a
% sizes array.
%
% Note that in this example, the values are hard coded.  This is not a
% recommended practice as the characteristics of the block are typically
% defined by the S-function parameters.
%
sizes = simsizes;

sizes.NumContStates  = 0;
sizes.NumDiscStates  = 3;
sizes.NumOutputs     = 1;
sizes.NumInputs      = 1;
sizes.DirFeedthrough = 0;
sizes.NumSampleTimes = 1;   % at least one sample time is needed

sys = simsizes(sizes);

%
% initialize the initial conditions
%
x0  = [0 0 0];

%
% str is always an empty matrix
%
str = [];

%
% initialize the array of sample times
%
ts  = [0.001 0];

% end mdlInitializeSizes

%
%=============================================================================
% mdlDerivatives
% Return the derivatives for the continuous states.
%=============================================================================
%
function sys=mdlDerivatives(t,x,u)

sys =[];

% end mdlDerivatives

%
%=============================================================================
% mdlUpdate
% Handle discrete state updates, sample time hits, and major time step
% requirements.
%=============================================================================
%
function sys=mdlUpdate(t,x,u)
if u>0
     if (u>0)&&(u<=16)
       sys=[10000000 0000000 zhuanhuan(abs(u))];
    elseif u>16&&u<=32
        sys=[10000000 0010000 zhuanhuan(abs(u))];
    elseif u>32&&u<=64
        sys=[10000000 0100000 zhuanhuan(abs((u-32)/2))];
    elseif u>64&&u<=128
        sys=[10000000 0110000 zhuanhuan(abs((u-64)/4))];
    elseif u>128&&u<=256
          sys=[10000000 1000000 zhuanhuan(abs((u-128)/8))];
    elseif  u>256&&u<=512
           sys=[10000000 1010000 zhuanhuan(abs((u-256)/16))];
    elseif u>512&&u<=1024x
           sys=[10000000 1100000 zhuanhuan(abs((u-512)/32))];
    elseif u>1024&&u<=2048
            sys=[10000000 1110000 zhuanhuan(abs((u-1024)/64))];
        end
else if u<0
       if abs(u)>0&&abs(u)<=16
         sys=[00000000 0000000 zhuanhuan(abs(u))];
      elseif u>16&&u<=32
        sys=[00000000 0010000 zhuanhuan(abs(u))];
      elseif u>32&&u<=64
        sys=[00000000 0100000 zhuanhuan(abs((u-32)/2))];
      elseif u>64&&u<=128
        sys=[00000000 0110000 zhuanhuan(abs((u-64)/4))];
      elseif u>128&&u<=256
          sys=[00000000 1000000 zhuanhuan(abs((u-128)/8))];
      elseif  u>256&&u<=512
           sys=[00000000 1010000 zhuanhuan(abs((u-256)/16))];
      elseif u>512&&u<=1024x
           sys=[00000000 1100000 zhuanhuan(abs((u-512)/32))];
      elseif u>1024&&u<=2048
            sys=[00000000 1110000 zhuanhuan(abs((u-1024)/64))];
        end 
    end
end
% end mdlUpdate

%
%=============================================================================
% mdlOutputs
% Return the block outputs.
%=============================================================================
%
function sys=mdlOutputs(t,x,u)

sys=x(1)+x(2)+x(3);
% end mdlOutputs

%
%=============================================================================
% mdlGetTimeOfNextVarHit
% Return the time of the next hit for this block.  Note that the result is
% absolute time.  Note that this function is only used when you specify a
% variable discrete-time sample time [-2 0] in the sample time array in
% mdlInitializeSizes.
%=============================================================================
%

% end mdlGetTimeOfNextVarHit

%
%=============================================================================
% mdlTerminate
% Perform any end of simulation tasks.
%=============================================================================
%
function sys=mdlTerminate(t,x,u)

sys = [];

% end mdlTerminate