diff --git a/src/xspice/icm/digital/d_xnor/cfunc.mod b/src/xspice/icm/digital/d_xnor/cfunc.mod
index 89c584d9b..09a042e1a 100644
--- a/src/xspice/icm/digital/d_xnor/cfunc.mod
+++ b/src/xspice/icm/digital/d_xnor/cfunc.mod
@@ -8,40 +8,33 @@ Public Domain
 Georgia Tech Research Corporation
 Atlanta, Georgia 30332
 PROJECT A-8503-405
-               
 
-AUTHORS                      
+AUTHORS
 
     18 Jun 1991     Jeffrey P. Murray
 
-
-MODIFICATIONS   
+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
 
-INTERFACES       
+    FILE                 ROUTINE CALLED
 
-    FILE                 ROUTINE CALLED     
+    CMutil.c             void cm_toggle_bit();
 
-    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
 
@@ -51,142 +44,116 @@ NON-STANDARD FEATURES
 
 /*=== INCLUDE FILES ====================*/
 
-
-                                      
+#include "ngspice/inertial.h"
 
 /*=== CONSTANTS ========================*/
 
 
-
-
 /*=== MACROS ===========================*/
 
 
+/*=== LOCAL VARIABLES & TYPEDEFS =======*/
 
-  
-/*=== LOCAL VARIABLES & TYPEDEFS =======*/                         
 
-
-    
-           
 /*=== FUNCTION PROTOTYPE DEFINITIONS ===*/
 
 
-
-
-                   
 /*==============================================================================
 
 FUNCTION cm_toggle_bit()
 
-
-AUTHORS                      
+AUTHORS
 
     27 Sept 1991     Jeffrey P. Murray
 
-
-MODIFICATIONS   
+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
 
-INTERFACES       
-
-    FILE                 ROUTINE CALLED     
+    FILE                 ROUTINE CALLED
 
     N/A                  N/A
 
-
 RETURNED VALUE
-    
-    No returned value. Passed pointer to variable is used 
+
+    No returned value. Passed pointer to variable is used
     to redefine the variable value.
-           
 
 GLOBAL VARIABLES
-    
-    NONE
 
+    NONE
 
 NON-STANDARD FEATURES
 
     NONE
-                                                   
+
 ===============================================================================*/
 
 /*=== CM_TOGGLE_BIT ROUTINE ===*/
 
-static void cm_toggle_bit(Digital_State_t *bit) 
-
+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 
+       bit value is UNKNOWN. In the latter case, return
        without changing the bit value.                      */
 
     if ( UNKNOWN != *bit ) {
         if ( ONE == *bit ) {
             *bit = ZERO;
         }
-        else { 
+        else {
             *bit = ONE;
         }
     }
-
 }
-                     
+
 
 /*==============================================================================
 
 FUNCTION cm_d_xnor()
 
-
-AUTHORS                      
+AUTHORS
 
     18 Jun 1991     Jeffrey P. Murray
 
-
-MODIFICATIONS   
+MODIFICATIONS
 
      7 Aug 1991     Jeffrey P. Murray
      2 Oct 1991     Jeffrey P. Murray
 
-
 SUMMARY
 
     This function implements the d_xnor code model.
 
+INTERFACES
 
-INTERFACES       
+    FILE                 ROUTINE CALLED
 
-    FILE                 ROUTINE CALLED     
+    CMutil.c             void cm_toggle_bit();
 
-    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
 
+    NONE
 
 NON-STANDARD FEATURES
 
     NONE
-                                                   
+
 ===============================================================================*/
 
 /*=== CM_D_XNOR ROUTINE ===*/
@@ -199,126 +166,129 @@ NON-STANDARD FEATURES
 *   Created 6/18/91              J.P.Murray     *
 ************************************************/
 
-
-void cm_d_xnor(ARGS) 
-
+void cm_d_xnor(ARGS)
 {
     int                    i,   /* generic loop counter index */
-	                    size;   /* number of input & output ports */
-         
-                        
+                        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  */    
+    Digital_State_t      val,
+                        *out,   /* temporary output for buffers */
+                       input;   /* temp storage for input bits  */
 
 
     /** Retrieve size value... **/
     size = PORT_SIZE(in);
 
-                                          
-
     /*** Setup required state variables ***/
 
-    if(INIT) {  /* initial pass */ 
-
+    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);
+        cm_event_alloc(0, sizeof (Digital_State_t));
 
-        /* retrieve storage for the outputs */
-        out = out_old = (Digital_State_t *) cm_event_get_ptr(0,0);
+        /* Inertial delay? */
 
-    }
-    else {      /* Retrieve previous values */
-                                              
+        STATIC_VAR(is_inertial) =
+            cm_is_inertial(PARAM_NULL(inertial_delay) ? Not_set :
+                         PARAM(inertial_delay));
+        if (STATIC_VAR(is_inertial)) {
+            /* Allocate storage for event time. */
+
+            cm_event_alloc(1, sizeof (struct idata));
+            ((struct idata *)cm_event_get_ptr(1, 0))->when = -1.0;
+        }
+
+        /* Prepare initial output. */
+
+        out = (Digital_State_t *)cm_event_get_ptr(0, 0);
+        *out = (Digital_State_t)(UNKNOWN + 1); // Force initial output.
+
+        for (i=0; i<size; i++) LOAD(in[i]) = PARAM(input_load);
+    } 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;
+    val = 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);
+        /* if a 1, toggle bit value */
+        if ( ONE == (input = INPUT_STATE(in[i])) ) {
+            cm_toggle_bit(&val);
+        } else {
+            /* if an unknown input, set val to unknown & break */
+            if ( UNKNOWN == input ) {
+                val = UNKNOWN;
+                break;
             }
-            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 **/
-
+    /*** Check for change and output appropriate values ***/
 
-        if ( *out != *out_old ) { /* output value is changing */
+    if (val == *out) { /* output value is not changing */
+        OUTPUT_CHANGED(out) = FALSE;
+    } else {
+        switch (val) {
 
-            switch ( *out ) {
-                                                 
             /* fall to zero value */
-            case 0: OUTPUT_STATE(out) = ZERO;
-                    OUTPUT_DELAY(out) = PARAM(fall_delay);
-                    break;
-    
+        case 0:
+            OUTPUT_DELAY(out) = PARAM(fall_delay);
+            break;
+
             /* rise to one value */
-            case 1: OUTPUT_STATE(out) = ONE;
-                    OUTPUT_DELAY(out) = PARAM(rise_delay);
-                    break;
-                                    
+        case 1:
+            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;
+        default:
+            /* based on old value, add rise or fall delay */
+            if (0 == *out) {  /* 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;
+        if (STATIC_VAR(is_inertial) && ANALYSIS == TRANSIENT) {
+            struct idata *idp;
+
+            idp = (struct idata *)cm_event_get_ptr(1, 0);
+            if (idp->when <= TIME) {
+                /* Normal transition. */
 
-} 
+                idp->prev = *out;
+                idp->when = TIME + OUTPUT_DELAY(out); // Actual output time
+            } else if (val != idp->prev) {
+                Digital_t ov = {idp->prev, STRONG};
 
-      
+                /* Third value: cancel earlier change and output as usual. */
 
+                cm_schedule_output(1, 0, (idp->when - TIME) / 2.0, &ov);
+		if (val == UNKNOWN) {
+                    /* Delay based in idp->prev, not *out. */
 
+                    if (idp->prev == ZERO)
+                        OUTPUT_DELAY(out) = PARAM(rise_delay);
+                    else
+                        OUTPUT_DELAY(out) = PARAM(fall_delay);
+                }
+                idp->when = TIME + OUTPUT_DELAY(out); // Actual output time
+            } else {
+                /* Changing back: override pending change. */
 
+                OUTPUT_DELAY(out) = (idp->when - TIME) / 2.0; // Override
+		idp->when = -1.0;
+            }
+        }
+        *out = val;
+        OUTPUT_STATE(out) = val;
+        OUTPUT_STRENGTH(out) = STRONG;
+    }
+}
diff --git a/src/xspice/icm/digital/d_xnor/ifspec.ifs b/src/xspice/icm/digital/d_xnor/ifspec.ifs
index ee858089b..e225f83ab 100644
--- a/src/xspice/icm/digital/d_xnor/ifspec.ifs
+++ b/src/xspice/icm/digital/d_xnor/ifspec.ifs
@@ -6,18 +6,18 @@ Georgia Tech Research Corporation
 Atlanta, Georgia 30332
 
 
-AUTHORS                      
+AUTHORS
 
      2 Oct 1991     Jeffrey P. Murray
 
 
 SUMMARY
 
-    This file contains the interface specification file for the 
+    This file contains the interface specification file for the
     digital d_xnor code model.
 
 ===============================================================================*/
- 
+
 NAME_TABLE:
 
 
@@ -33,31 +33,49 @@ Description:         "input"            "output"
 Direction:           in                 out
 Default_Type:        d                  d
 Allowed_Types:       [d]                [d]
-Vector:               yes                no
-Vector_Bounds:        [2 -]              -
+Vector:              yes                no
+Vector_Bounds:       [2 -]              -
 Null_Allowed:        no                 no
 
 
 PARAMETER_TABLE:
 
-Parameter_Name:     rise_delay                  fall_delay	
+Parameter_Name:     rise_delay                  fall_delay
 Description:        "rise delay"                "fall delay"
-Data_Type:          real                        real   
-Default_Value:      1.0e-9                      1.0e-9  
-Limits:             [1e-12 -]                   [1e-12 -]       
+Data_Type:          real                        real
+Default_Value:      1.0e-9                      1.0e-9
+Limits:             [1e-12 -]                   [1e-12 -]
 Vector:              no                          no
 Vector_Bounds:       -                           -
-Null_Allowed:       yes                         yes    
+Null_Allowed:       yes                         yes
 
 
 PARAMETER_TABLE:
 
-Parameter_Name:     input_load
-Description:        "input load value (pF)" 
-Data_Type:          real                          
-Default_Value:      1.0                    
-Limits:             [0.0 -]                                 
-Vector:              no                         
-Vector_Bounds:       -                         
-Null_Allowed:       yes                            
+Parameter_Name:     input_load			family
+Description:        "input load value (F)"	"Logic family for bridging"
+Data_Type:          real                        string
+Default_Value:      1.0e-12                     -
+Limits:             -                           -
+Vector:              no                         no
+Vector_Bounds:      -                           -
+Null_Allowed:       yes                         yes
+
+
+PARAMETER_TABLE:
+
+Parameter_Name:     inertial_delay
+Description:        "swallow short pulses"
+Data_Type:          boolean
+Default_Value:      false
+Limits:             -
+Vector:             no
+Vector_Bounds:      -
+Null_Allowed:       yes
+
+
+STATIC_VAR_TABLE:
 
+Static_Var_Name:    is_inertial
+Data_Type:	    boolean
+Description:        "using inertial delay"
diff --git a/src/xspice/icm/digital/d_xor/cfunc.mod b/src/xspice/icm/digital/d_xor/cfunc.mod
index b4ad95961..8e83a9a18 100644
--- a/src/xspice/icm/digital/d_xor/cfunc.mod
+++ b/src/xspice/icm/digital/d_xor/cfunc.mod
@@ -157,9 +157,7 @@ NON-STANDARD FEATURES
 *   Created 6/18/91               J.P.Murray    *
 ************************************************/
 
-
 void cm_d_xor(ARGS)
-
 {
     int                    i,   /* generic loop counter index */
                         size;   /* number of input & output ports */
@@ -285,8 +283,3 @@ void cm_d_xor(ARGS)
         OUTPUT_STRENGTH(out) = STRONG;
     }
 }
-
-
-
-
-