Add function cm_get_neg_node_name

as cm_get_node_name delivers only the pos node.

src/include/ngspice/cmproto.h

@@ -99,6 +99,7 @@ double cm_netlist_get_l(void);
 
 void        cm_irreversible(unsigned int);
 const char *cm_get_node_name(const char *, unsigned int);
+const char *cm_get_neg_node_name(const char *, unsigned int);
 bool        cm_probe_node(unsigned int, unsigned int, void *);
 bool        cm_schedule_output(unsigned int, unsigned int, double, void *);
 

src/include/ngspice/dllitf.h

@@ -61,6 +61,7 @@ struct coreInfo_t {
 	double    ((*dllitf_cm_netlist_get_l)(void));
         void      ((*dllitf_cm_irreversible)(unsigned int));
     const char *  ((*dllitf_cm_get_node_name)(const char *, unsigned int));
+	const char* ((*dllitf_cm_get_neg_node_name)(const char*, unsigned int));
     bool          ((*dllitf_cm_probe_node)(unsigned int, unsigned int,
                                            void *));
         bool      ((*dllitf_cm_schedule_output)(unsigned int, unsigned int,

src/xspice/cm/cm.c

@@ -40,6 +40,7 @@ INTERFACES
 
     cm_irreversible()
     cm_get_node_name()
+    cm_get_neg_node_name()
     cm_probe_node()
 
 REFERENCED FILES
@@ -852,6 +853,33 @@ const char *cm_get_node_name(const char *port_name, unsigned int index)
     return NULL;
 }
 
+/* Get the neg name of a circuit node connected to a port. */
+
+const char* cm_get_neg_node_name(const char* port_name, unsigned int index)
+{
+    MIFinstance* instance;
+    Mif_Conn_Data_t* conn;
+    Mif_Port_Data_t* port;
+    int               i;
+
+    instance = g_mif_info.instance;
+    for (i = 0; i < instance->num_conn; ++i) {
+        conn = instance->conn[i];
+        if (!strcmp(port_name, conn->name)) {
+            if (index >= (unsigned int)conn->size)
+                return NULL;
+            port = conn->port[index];
+            if (port->type == MIF_DIGITAL || port->type == MIF_USER_DEFINED) {
+                /* Event node, no name in port data. */
+                return NULL;
+            }
+            return port->neg_node_str;
+        }
+    }
+    return NULL;
+}
+
+
 /* Test the resolved value of a connected Digital/UDN node, given
  * an assumed value for a particular port.
  */

src/xspice/cm/cmexport.c

@@ -60,6 +60,7 @@ struct coreInfo_t  coreInfo =
   cm_netlist_get_l,
   cm_irreversible,
   cm_get_node_name,
+  cm_get_neg_node_name,
   cm_probe_node,
   cm_schedule_output,
   cp_getvar,

src/xspice/icm/dlmain.c

@@ -350,6 +350,10 @@ const char *cm_get_node_name(const char *port, unsigned int index) {
     return coreitf->dllitf_cm_get_node_name(port, index);
 }
 
+const char *cm_get_neg_node_name(const char *port, unsigned int index) {
+    return coreitf->dllitf_cm_get_neg_node_name(port, index);
+}
+
 bool cm_probe_node(unsigned int  conn_index,
                    unsigned int  port_index,
                    void         *value) {