cm.c

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        (byte_index > ((ckt->CKTnumStates - 1) * sizeof(double)) ) ) {
        g_mif_info.errmsg =
        "ERROR - cm_analog_converge() - Argument must be in state vector 0\n";
        return(MIF_ERROR);
    }

    /* Scan the conv array in the instance struct to see if already registered */
    /* If so, do nothing, just return */
    for(i = 0; i < here->num_conv; i++) {
        if(here->conv[i].byte_index == byte_index)
            return(MIF_OK);
    }

    /* Allocate space in instance struct for this conv descriptor */
    if(here->num_conv == 0) {
        here->num_conv = 1;
        here->conv = (void *) MALLOC(sizeof(Mif_Conv_t));
    }
    else {
        here->num_conv++;
        here->conv = (void *) REALLOC(here->conv,
                                       here->num_conv * sizeof(Mif_Conv_t));
    }

    /* Fill in the conv descriptor data */
    conv = &(here->conv[here->num_conv - 1]);
    conv->byte_index = byte_index;
    conv->last_value = 1.0e30;      /* There should be a better way ... */

    return(MIF_OK);
}



/*
cm_message_get_errmsg()

This function returns the address of an error message string set
by a call to some code model support function.
*/

char *cm_message_get_errmsg(void)
{
    return(g_mif_info.errmsg);
}




/*
cm_analog_set_temp_bkpt()

This function is called by a code model C function to set a
temporary breakpoint.  These temporary breakpoints remain in
effect only until the next timestep is taken.  A temporary
breakpoint added with a time less than the current time, but
greater than the last successful timestep causes the simulator to
abandon the current timestep and decrease the timestep to hit the
breakpoint.  A temporary breakpoint with a time greater than the
current time causes the simulator to make the breakpoint the next
timepoint if the next timestep would produce a time greater than
that of the breakpoint.
*/


int cm_analog_set_temp_bkpt(
    double time)              /* The time of the breakpoint to be set */
{
    CKTcircuit  *ckt;


    /* Get the address of the ckt and instance structs from g_mif_info */
    ckt  = g_mif_info.ckt;

    /* Make sure breakpoint is not prior to last accepted timepoint */
    if(time < ((ckt->CKTtime - ckt->CKTdelta) + ckt->CKTminBreak)) {
        g_mif_info.errmsg =
        "ERROR - cm_analog_set_temp_bkpt() - Time < last accepted timepoint\n";
        return(MIF_ERROR);
    }

    /* If too close to a permanent breakpoint or the current time, discard it */
    if( (fabs(time - ckt->CKTbreaks[0]) < ckt->CKTminBreak) ||
        (fabs(time - ckt->CKTbreaks[1]) < ckt->CKTminBreak) ||
        (fabs(time - ckt->CKTtime) < ckt->CKTminBreak) )
        return(MIF_OK);

    /* If < current dynamic breakpoint, make it the current breakpoint */
    if( time < g_mif_info.breakpoint.current)
        g_mif_info.breakpoint.current = time;

    return(MIF_OK);
}




/*
cm_analog_set_perm_bkpt()

This function is called by a code model C function to set a
permanent breakpoint.  These permanent breakpoints remain in
effect from the time they are introduced until the simulation
time equals or exceeds the breakpoint time.  A permanent
breakpoint added with a time less than the current time, but
greater than the last successful timestep causes the simulator to
abandon the current timestep and decrease the timestep to hit the
breakpoint.  A permanent breakpoint with a time greater than the
current time causes the simulator to make the breakpoint the next
timepoint if the next timestep would produce a time greater than
that of the breakpoint.
*/


int cm_analog_set_perm_bkpt(
    double time)              /* The time of the breakpoint to be set */
{
    CKTcircuit  *ckt;


    /* Get the address of the ckt and instance structs from g_mif_info */
    ckt  = g_mif_info.ckt;

    /* Call cm_analog_set_temp_bkpt() to force backup if less than current time */
    if(time < (ckt->CKTtime + ckt->CKTminBreak))
        return(cm_analog_set_temp_bkpt(time));
    else
        CKTsetBreak(ckt,time);

    return(MIF_OK);
}


/*
cm_analog_ramp_factor()

This function returns the current value of the ramp factor
associated with the ``ramptime'' option.  For this option
to work best, models with analog outputs that may be non-zero at
time zero should call this function and scale their outputs
and partials by the ramp factor.
*/


double cm_analog_ramp_factor(void)
{

    CKTcircuit  *ckt;

    /* Get the address of the ckt and instance structs from g_mif_info */
    ckt  = g_mif_info.ckt;


    /* if ramptime == 0.0, no ramptime option given, so return 1.0 */
    /* this is the most common case, so it goes first */
    if(ckt->enh->ramp.ramptime == 0.0)
        return(1.0);

    /* else if not transient analysis, return 1.0 */
    else if( (!(ckt->CKTmode & MODETRANOP)) && (!(ckt->CKTmode & MODETRAN)) )
        return(1.0);

    /* else if time >= ramptime, return 1.0 */
    else if(ckt->CKTtime >= ckt->enh->ramp.ramptime)
        return(1.0);

    /* else time < end of ramp, so compute and return factor based on time */
    else
        return(ckt->CKTtime / ckt->enh->ramp.ramptime);
}


/* ************************************************************ */


/*
 * Copyright (c) 1985 Thomas L. Quarles
 *
 * This is a modified version of the function NIintegrate()
 *
 * Modifications are Copyright 1991 Georgia Tech Research Institute
 *
 */

static void cm_static_integrate(int    byte_index,
                                double integrand,
                                double *integral,
                                double *partial)
{
    CKTcircuit  *ckt;

    double  intgr[7];
    double  cur=0;
    double  *double_ptr;

    double  ceq;
    double  geq;

    char    *char_ptr;

    int     i;


    /* Get the address of the ckt struct from g_mif_info */
    ckt  = g_mif_info.ckt;

    /* Get integral values from current and previous timesteps */
    for(i = 0; i <= ckt->CKTorder; i++) {
        char_ptr = (char *) ckt->CKTstates[i];
        char_ptr += byte_index;
        double_ptr = (double *) char_ptr;
        intgr[i] = *double_ptr;
    }


    /* Do what SPICE3C1 does for its implicit integration */

    switch(ckt->CKTintegrateMethod) {

    case TRAPEZOIDAL:

        switch(ckt->CKTorder) {

        case 1:
            cur = ckt->CKTag[1] * intgr[1];
            break;

        case 2:
            /* WARNING - This code needs to be redone.  */
            /* The correct code should rely on one previous value */
            /* of cur as done in NIintegrate() */
            cur = -0.5 * ckt->CKTag[0] * intgr[1];
            break;
        }

        break;

    case GEAR:
        cur = 0.0;

        switch(ckt->CKTorder) {

        case 6:
            cur += ckt->CKTag[6] * intgr[6];
            /* fall through */
        case 5:
            cur += ckt->CKTag[5] * intgr[5];
            /* fall through */
        case 4:
            cur += ckt->CKTag[4] * intgr[4];
            /* fall through */
        case 3:
            cur += ckt->CKTag[3] * intgr[3];
            /* fall through */
        case 2:
            cur += ckt->CKTag[2] * intgr[2];
            /* fall through */
        case 1:
            cur += ckt->CKTag[1] * intgr[1];
            break;

        }
        break;

    }

    ceq = cur;
    geq = ckt->CKTag[0];

    /* WARNING: Take this out when the case 2: above is fixed */
    if((ckt->CKTintegrateMethod == TRAPEZOIDAL) &&
       (ckt->CKTorder == 2))
        geq *= 0.5;


    /* The following code is equivalent to */
    /* the solution of one matrix iteration to produce the  */
    /* integral value.                                      */

    *integral = (integrand - ceq) / geq;
    *partial  = 1.0 / geq;

}





/*
cm_analog_not_converged()

This function tells the simulator not to allow the current
iteration to be the final iteration.  It is called when
a code model performs internal limiting on one or more of
its inputs to assist convergence.
*/

void cm_analog_not_converged(void)
{
    (g_mif_info.ckt->CKTnoncon)++;
}




/*
cm_message_send()

This function prints a message output from a code model, prepending
the instance name.
*/


int cm_message_send(
    char *msg)        /* The message to output. */
{
    MIFinstance *here;

    /* Get the address of the instance struct from g_mif_info */
    here = g_mif_info.instance;

    /* Print the name of the instance and the message */
    printf("\nInstance: %s   Message: %s\n", (char *) here->MIFname, msg);

    return(0);
}






/*
cm_analog_auto_partial()

This function tells the simulator to automatically compute
approximations of partial derivatives of analog outputs
with respect to analog inputs.  When called from a code
model, it sets a flag in the g_mif_info structure
which tells function MIFload() and it's associated
MIFauto_partial() function to perform the necessary
calculations.
*/


void cm_analog_auto_partial(void)
{
    g_mif_info.auto_partial.local = MIF_TRUE;
}