text: /*
   * sfuntmpl_basic.c: Basic 'C' template for a level 2 S-function.
   *
   * Copyright 1990-2018 The MathWorks, Inc.
   */
  
  
  /*
   * You must specify the S_FUNCTION_NAME as the name of your S-function
   * (i.e. replace sfuntmpl_basic with the name of your S-function).
   */
  
  #define S_FUNCTION_NAME  BOOST
  #define S_FUNCTION_LEVEL 2
  #define unit unsigned int
  
  
  /*
   * Need to include simstruc.h for the definition of the SimStruct and
   * its associated macro definitions.
   */
  #include "simstruc.h"
  
  struct P
  {
      unit CNT;  // 计数器
      unit PRD;  // 最大值
      unit DIR;  // 计数方向
      unit CMP; 
  }PI;
  
  /* Error handling
   * --------------
   *
   * You should use the following technique to report errors encountered within
   * an S-function:
   *
   *       ssSetErrorStatus(S,"Error encountered due to ...");
   *       return;
   *
   * Note that the 2nd argument to ssSetErrorStatus must be persistent memory.
   * It cannot be a local variable. For example the following will cause
   * unpredictable errors:
   *
   *      mdlOutputs()
   *      {
   *         char msg[256];         {ILLEGAL: to fix use "static char msg[256];"}
   *         sprintf(msg,"Error due to %s", string);
   *         ssSetErrorStatus(S,msg);
   *         return;
   *      }
   *
   */
  
  /*====================*
   * S-function methods *
   *====================*/
  
  /* Function: mdlInitializeSizes ===============================================
   * Abstract:
   *    The sizes information is used by Simulink to determine the S-function
   *    block's characteristics (number of inputs, outputs, states, etc.).
   */
  static void mdlInitializeSizes(SimStruct *S)
  {
      ssSetNumSFcnParams(S, 0);  /* Number of expected parameters */
      if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S)) {
          /* Return if number of expected != number of actual parameters */
          return;
  }
  
      ssSetNumContStates(S, 0);
      ssSetNumDiscStates(S, 0);
  
      if (!ssSetNumInputPorts(S, 1)) return;
      ssSetInputPortWidth(S, 0, 1);
      ssSetInputPortRequiredContiguous(S, 0, true); /*direct input signal access*/
      /*
       * Set direct feedthrough flag (1=yes, 0=no).
       * A port has direct feedthrough if the input is used in either
       * the mdlOutputs or mdlGetTimeOfNextVarHit functions.
       */
      ssSetInputPortDirectFeedThrough(S, 0, 1);
  
      if (!ssSetNumOutputPorts(S, 1)) return;
      ssSetOutputPortWidth(S, 0, 3);
  
      ssSetNumSampleTimes(S, 1);
      ssSetNumRWork(S, 0);
      ssSetNumIWork(S, 0);
      ssSetNumPWork(S, 0);
      ssSetNumModes(S, 0);
      ssSetNumNonsampledZCs(S, 0);
  
      /* Specify the operating point save/restore compliance to be same as a 
       * built-in block */
      ssSetOperatingPointCompliance(S, USE_DEFAULT_OPERATING_POINT);
  
      ssSetOptions(S, 0);
  }
  
  
  
  /* Function: mdlInitializeSampleTimes =========================================
   * Abstract:
   *    This function is used to specify the sample time(s) for your
   *    S-function. You must register the same number of sample times as
   *    specified in ssSetNumSampleTimes.
   */
  static void mdlInitializeSampleTimes(SimStruct *S)
  {
      ssSetSampleTime(S, 0, 2.5e-8);
      ssSetOffsetTime(S, 0, 0.0);
  
  }
  
  
  
  #define MDL_INITIALIZE_CONDITIONS   /* Change to #undef to remove function */
  #if defined(MDL_INITIALIZE_CONDITIONS)
    /* Function: mdlInitializeConditions ========================================
     * Abstract:
     *    In this function, you should initialize the continuous and discrete
     *    states for your S-function block.  The initial states are placed
     *    in the state vector, ssGetContStates(S) or ssGetRealDiscStates(S).
     *    You can also perform any other initialization activities that your
     *    S-function may require. Note, this routine will be called at the
     *    start of simulation and if it is present in an enabled subsystem
     *    configured to reset states, it will be call when the enabled subsystem
     *    restarts execution to reset the states.
     */
    static void mdlInitializeConditions(SimStruct *S)
    {
        PI.CNT=0;
        PI.PRD=400; 
        PI.DIR=0;
        PI.CMP=120;
    }
  #endif /* MDL_INITIALIZE_CONDITIONS */
  
  
  
  #define MDL_START  /* Change to #undef to remove function */
  #if defined(MDL_START) 
    /* Function: mdlStart =======================================================
     * Abstract:
     *    This function is called once at start of model execution. If you
     *    have states that should be initialized once, this is the place
     *    to do it.
     */
    static void mdlStart(SimStruct *S)
    {
    }
  #endif /*  MDL_START */
  
  
  
  /* Function: mdlOutputs =======================================================
   * Abstract:
   *    In this function, you compute the outputs of your S-function
   *    block.
   */
  static void mdlOutputs(SimStruct *S, int_T tid)
  {
      const real_T *u = (const real_T*) ssGetInputPortSignal(S,0);
      real_T       *y = ssGetOutputPortSignal(S,0);
      real_T       *IL = ssGetOutputPortSignal(S,1);
      if(PI.DIR==0)
      {
          PI.CNT++;
      }
      if(PI.DIR==1)
      {
          PI.CNT--;
      }
      if(PI.CNT==PI.PRD)
      {
          PI.DIR = !PI.DIR;
      }
      if(PI.CNT==0)
      {
          PI.DIR = !PI.DIR;
          IL[0]=u[0];
      }
      if(PI.CNT>=0 && PI.CNT<=PI.CMP)
          y[2]=1;
      else
          y[2]=0;
      y[0] = PI.CNT;
      y[1] = PI.CMP;
      
  }
  
  
  
  #define MDL_UPDATE  /* Change to #undef to remove function */
  #if defined(MDL_UPDATE)
    /* Function: mdlUpdate ======================================================
     * Abstract:
     *    This function is called once for every major integration time step.
     *    Discrete states are typically updated here, but this function is useful
     *    for performing any tasks that should only take place once per
     *    integration step.
     */
    static void mdlUpdate(SimStruct *S, int_T tid)
    {
    }
  #endif /* MDL_UPDATE */
  
  
  
  #define MDL_DERIVATIVES  /* Change to #undef to remove function */
  #if defined(MDL_DERIVATIVES)
    /* Function: mdlDerivatives =================================================
     * Abstract:
     *    In this function, you compute the S-function block's derivatives.
     *    The derivatives are placed in the derivative vector, ssGetdX(S).
     */
    static void mdlDerivatives(SimStruct *S)
    {
    }
  #endif /* MDL_DERIVATIVES */
  
  
  
  /* Function: mdlTerminate =====================================================
   * Abstract:
   *    In this function, you should perform any actions that are necessary
   *    at the termination of a simulation.  For example, if memory was
   *    allocated in mdlStart, this is the place to free it.
   */
  static void mdlTerminate(SimStruct *S)
  {
  }
  
  
  /*=============================*
   * Required S-function trailer *
   *=============================*/
  
  #ifdef  MATLAB_MEX_FILE    /* Is this file being compiled as a MEX-file? */
  #include "simulink.c"      /* MEX-file interface mechanism */
  #else
  #include "cg_sfun.h"       /* Code generation registration function */
  #endif
  