simbi2de.c

数字通信第四版原书的例程

/*
 * simbi2de  binary to decimal conversion for SIMULINK block
 *
 *           Syntax:  [sys, x0] = simbi2de(t,x,u,flag,p)
 *                          where p is the calculation base.
 * Wes Wang 6/14/94
 * Copyright (c) 1994-96 The MathWorks, Inc.
 * All Rights Reserved
 * $Revision: 1.1 $  $Date: 1996/04/01 19:04:24 $
 */

/* specify the name of this S-Function. */
#define S_FUNCTION_NAME simbi2de

/* Defines for easy access  the matrices which are passed in */
#define NUM_ARGS    1
#define CAL_BASE    ssGetArg(S, 0)

#include "simstruc.h"
/*
 * mdlInitializeSizes - initialize the sizes array
 */

static void mdlInitializeSizes (S)
    SimStruct *S;
{
        ssSetNumContStates(    S, 0); /* number of continuous states */
        ssSetNumDiscStates(    S, 0);       /* number of discrete states */
        ssSetNumInputs    (    S, -1);   /* number of inputs */
        ssSetNumOutputs   (    S, 1);   /* number of outputs */
        ssSetDirectFeedThrough(S, 1);       /* direct feedthrough flag */
        ssSetNumSampleTimes(   S, 1);       /* number of sample times */
        ssSetNumInputArgs(     S, NUM_ARGS);/* number of input arguments */
        ssSetNumRWork(         S, 0);       /* number of real work vector elements */
        ssSetNumIWork(         S, 0);      /* number of integer work vector elements */
        ssSetNumPWork(         S, 0);      /* number of pointer work vector elements */
}

/*
 * mdlInitializeSampleTimes - initialize the sample times array
 *
 * This function is used to specify the sample time(s) for your S-function.
 * If your S-function is continuous, you must specify a sample time of 0.0.
 * Sample times must be registered in ascending order.
 */

static void mdlInitializeSampleTimes(S)
    SimStruct *S;
{
    ssSetSampleTimeEvent(S, 0, 0.0);
    ssSetOffsetTimeEvent(S, 0, 0.0);
}

/*
 * mdlInitializeConditions - initialize the states
 * Initialize the states, Integers and real-numbers
 */

static void mdlInitializeConditions(x0, S)
        double *x0;
        SimStruct *S;
{
}

/*
 * mdlOutputs - compute the outputs
 *
 * In this function, you compute the outputs of your S-function
 * block.  The outputs are placed in the y variable.
 */

static void mdlOutputs(y, x, u, S, tid)
    double *y, *x, *u;
    SimStruct *S;
    int tid;
{
    long inSize, i, pow, p;

    inSize = (int)ssGetNumInputs(S);
    p = (int)mxGetPr(CAL_BASE)[0];
    if (p < 2)
        p = 2;    
    y[0] = 0;
    pow = 1;
    for (i=0; i <inSize; i++) {
         y[0] += (double)(abs((int)u[i]) % p * pow);
         pow  *= p;
    }
}


/*
 * mdlUpdate - perform action at major integration time step
 *
 * 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(x, u, S, tid)
    double *x, *u;
    SimStruct *S;
    int tid;
{
}

/*
 * mdlDerivatives - compute the derivatives
 *
 * In this function, you compute the S-function block's derivatives.
 * The derivatives are placed in the dx variable.
 */

static void mdlDerivatives(dx, x, u, S, tid)
    double *dx, *x, *u;
    SimStruct *S;
    int tid;
{
}

/*
 * mdlTerminate - called when the simulation is terminated.
 *
 * In this function, you should perform any actions that are necessary
 * at the termination of a simulation.  For example, if memory was allocated
 * in mdlInitializeConditions, this is the place to free it.
 */

static void mdlTerminate(S)
    SimStruct *S;
{
}

#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