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/* 
 * MODULINT  A modulate integrator. 
 *           (see manual under Advanced Topics). 
 * 
 *           Syntax:  [sys, x0] = moldulint(t,x,u,flag,x0,lowbd,upbd) 
 * 
 * Wes Wang 5/5/94 
 * Copyright (c) 1994-96 The MathWorks, Inc. 
 * All Rights Reserved 
 * $Revision: 1.1 $  $Date: 1996/04/01 19:03:19 $ 
 */ 
 
#undef MODEL_NAME 
#define MODEL_NAME modulint 
 
#define X0  ssGetArg(S, 0) 
 
/* 
 * need to include simstruc.h for the definition of the SimStruct and 
 * its associated macro definitions. 
 */ 
 
#include "simstruc.h" 
 
/* 
 * mdlInitializeSizes - called to initialize the sizes array stored in 
 *                      the SimStruct.  The sizes array defines the 
 *                      characteristics (number of inputs, outputs, 
 *                      states, etc.) of the S-Function. 
 */ 
 
static void mdlInitializeSizes (S) 
    SimStruct *S; 
{ 
    /* 
     * Set-up size information. 
     */ 
     
    ssSetNumContStates(    S, 1); 
    ssSetNumDiscStates(    S, 0); 
    ssSetNumOutputs(       S, 1); 
    ssSetNumInputs(        S, 1); 
    ssSetDirectFeedThrough(S, 0); 
    ssSetNumSampleTimes(   S, 1); 
    ssSetNumRWork(         S, 0); 
    ssSetNumIWork(         S, 0); 
    ssSetNumInputArgs(     S, 3); 
} 
 
/* 
 * mdlInitializeSampleTimes - initializes the array of sample times stored in 
 *                            the SimStruct associated with this S-Function. 
 */ 
 
static void mdlInitializeSampleTimes(S) 
    SimStruct *S; 
{ 
    ssSetSampleTimeEvent(S, 0, 0.); 
    ssSetOffsetTimeEvent(S, 0, 0.); 
} 
 
/* 
 * mdlInitializeConditions - initializes the states for the S-Function 
 */ 
 
static void mdlInitializeConditions(x0, S) 
    double *x0; 
    SimStruct *S; 
{ 
    if ((mxGetM(X0) == 0) || (mxGetN(X0) == 0)) 
     *x0 = 0.; 
    else 
       *x0 = mxGetPr(X0)[0]; 
} 
 
/* 
 * mdlOutputs - computes the outputs of the S-Function 
 */ 
 
static void mdlOutputs(y, x, u, S, tid) 
    double *y, *x, *u; 
    SimStruct *S; 
    int tid; 
{ 
    y[0] = x[0]; 
} 
 
/* 
 * mdlUpdate - computes the discrete states of the S-Function 
 */ 
 
static void mdlUpdate(x, u, S, tid) 
    double *x, *u; 
    SimStruct *S; 
    int tid; 
{ 
    Matrix *mx_up, *mx_low; 
    double bd_up, bd_low, differ; 
 
    mx_up = ssGetArg(S,1); 
    mx_low = ssGetArg(S,2); 
 
    if ((mxGetM(mx_up) == 0) || (mxGetN(mx_up) == 0))     
      bd_up = 0; 
    else 
      bd_up = mxGetPr(ssGetArg(S,2))[0]; 
 
    if ((mxGetM(mx_low) == 0) || (mxGetN(mx_low) == 0))     
      bd_low = 0; 
    else 
      bd_low = mxGetPr(ssGetArg(S,1))[0]; 
 
    differ = bd_up - bd_low; 
 
    if (differ > 0.0) { 
      while (u[0] < bd_low) 
        x[0] = x[0] + differ; 
      while (x[0] > bd_up) 
        x[0] = x[0] - differ; 
    } 
} 
 
/* 
 * mdlDerivatives - computes the derivatives of the S-Function 
 */ 
 
static void mdlDerivatives(dx, x, u, S, tid) 
    double *dx, *x, *u; 
    SimStruct *S; 
    int tid; 
{ 
    dx[0] = u[0]; 
} 
 
/* 
 * mdlTerminate - called at termination of model execution. 
 */ 
 
static void mdlTerminate(S) 
    SimStruct *S; 
{ 
} 
 
#ifdef    MATLAB_MEX_FILE    /* Is this file being compiled as a MEX-file? */ 
#include "simulink.c"      /* MEX glue */ 
#else 
#include "cg_glue.h"       /* Code generation glue */ 
#endif