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/*.......1.........2.........3.........4.........5.........6.........7.........8
================================================================================
FILE d_xnor/cfunc.mod
Public Domain
Georgia Tech Research Corporation
Atlanta, Georgia 30332
PROJECT A-8503-405
AUTHORS
18 Jun 1991 Jeffrey P. Murray
MODIFICATIONS
7 Aug 1991 Jeffrey P. Murray
2 Oct 1991 Jeffrey P. Murray
SUMMARY
This file contains the model-specific routines used to
functionally describe the d_xnor code model.
INTERFACES
FILE ROUTINE CALLED
CMutil.c void cm_toggle_bit();
CMevt.c void *cm_event_alloc()
void *cm_event_get_ptr()
REFERENCED FILES
Inputs from and outputs to ARGS structure.
NON-STANDARD FEATURES
NONE
===============================================================================*/
/*=== INCLUDE FILES ====================*/
/*=== CONSTANTS ========================*/
/*=== MACROS ===========================*/
/*=== LOCAL VARIABLES & TYPEDEFS =======*/
/*=== FUNCTION PROTOTYPE DEFINITIONS ===*/
/*==============================================================================
FUNCTION cm_toggle_bit()
AUTHORS
27 Sept 1991 Jeffrey P. Murray
MODIFICATIONS
NONE
SUMMARY
Alters the state of a passed digital variable to its
complement. Thus, a ONE changes to a ZERO. A ZERO changes
to a ONE, and an UNKNOWN remains unchanged.
INTERFACES
FILE ROUTINE CALLED
N/A N/A
RETURNED VALUE
No returned value. Passed pointer to variable is used
to redefine the variable value.
GLOBAL VARIABLES
NONE
NON-STANDARD FEATURES
NONE
===============================================================================*/
/*=== CM_TOGGLE_BIT ROUTINE ===*/
static void cm_toggle_bit(Digital_State_t *bit)
{
/* Toggle bit from ONE to ZERO or vice versa, unless the
bit value is UNKNOWN. In the latter case, return
without changing the bit value. */
if ( UNKNOWN != *bit ) {
if ( ONE == *bit ) {
*bit = ZERO;
}
else {
*bit = ONE;
}
}
}
/*==============================================================================
FUNCTION cm_d_xnor()
AUTHORS
18 Jun 1991 Jeffrey P. Murray
MODIFICATIONS
7 Aug 1991 Jeffrey P. Murray
2 Oct 1991 Jeffrey P. Murray
SUMMARY
This function implements the d_xnor code model.
INTERFACES
FILE ROUTINE CALLED
CMutil.c void cm_toggle_bit();
CMevt.c void *cm_event_alloc()
void *cm_event_get_ptr()
RETURNED VALUE
Returns inputs and outputs via ARGS structure.
GLOBAL VARIABLES
NONE
NON-STANDARD FEATURES
NONE
===============================================================================*/
/*=== CM_D_XNOR ROUTINE ===*/
/************************************************
* The following is the model for the *
* digital XNOR gate for the *
* ATESSE Version 2.0 system. *
* *
* Created 6/18/91 J.P.Murray *
************************************************/
void cm_d_xnor(ARGS)
{
int i, /* generic loop counter index */
size; /* number of input & output ports */
Digital_State_t *out, /* temporary output for buffers */
*out_old, /* previous output for buffers */
input; /* temp storage for input bits */
/** Retrieve size value... **/
size = PORT_SIZE(in);
/*** Setup required state variables ***/
if(INIT) { /* initial pass */
/* allocate storage for the outputs */
cm_event_alloc(0,sizeof(Digital_State_t));
for (i=0; i<size; i++) LOAD(in[i]) = PARAM(input_load);
/* retrieve storage for the outputs */
out = out_old = (Digital_State_t *) cm_event_get_ptr(0,0);
}
else { /* Retrieve previous values */
/* retrieve storage for the outputs */
out = (Digital_State_t *) cm_event_get_ptr(0,0);
out_old = (Digital_State_t *) cm_event_get_ptr(0,1);
}
/*** Calculate new output value based on inputs ***/
*out = ONE;
for (i=0; i<size; i++) {
/* make sure this input isn't floating... */
if ( FALSE == PORT_NULL(in) ) {
/* if a 1, toggle bit value */
if ( ONE == (input = INPUT_STATE(in[i])) ) {
cm_toggle_bit(out);
}
else {
/* if an unknown input, set *out to unknown & break */
if ( UNKNOWN == input ) {
*out = UNKNOWN;
break;
}
}
}
else {
/* at least one port is floating...output is unknown */
*out = UNKNOWN;
break;
}
}
/*** Determine analysis type and output appropriate values ***/
if (ANALYSIS == DC) { /** DC analysis...output w/o delays **/
OUTPUT_STATE(out) = *out;
}
else { /** Transient Analysis **/
if ( *out != *out_old ) { /* output value is changing */
switch ( *out ) {
/* fall to zero value */
case 0: OUTPUT_STATE(out) = ZERO;
OUTPUT_DELAY(out) = PARAM(fall_delay);
break;
/* rise to one value */
case 1: OUTPUT_STATE(out) = ONE;
OUTPUT_DELAY(out) = PARAM(rise_delay);
break;
/* unknown output */
default:
OUTPUT_STATE(out) = *out = UNKNOWN;
/* based on old value, add rise or fall delay */
if (0 == *out_old) { /* add rising delay */
OUTPUT_DELAY(out) = PARAM(rise_delay);
}
else { /* add falling delay */
OUTPUT_DELAY(out) = PARAM(fall_delay);
}
break;
}
}
else { /* output value not changing */
OUTPUT_CHANGED(out) = FALSE;
}
}
OUTPUT_STRENGTH(out) = STRONG;
}