Add .options wnflag = 0|1 to unselect|select

nf as a divisor for w/nf while model binning.
Enable reading wnflag from the instance line.

src/spicelib/parser/inpgmod.c

@@ -224,22 +224,45 @@ INPgetModBin(CKTcircuit *ckt, char *name, INPmodel **model, INPtables *tab, char
     double       l, w, lmin, lmax, wmin, wmax;
     double       parse_values[4];
     bool         parse_found[4];
-    static char *instance_tokens[] = { "l", "w", "nf" };
+    static char *instance_tokens[] = { "l", "w", "nf", "wnflag" };
     static char *model_tokens[]    = { "lmin", "lmax", "wmin", "wmax" };
     double       scale;
+    int          wnflag;
 
     if (!cp_getvar("scale", CP_REAL, &scale, 0))
         scale = 1;
 
+    if (!cp_getvar("wnflag", CP_NUM, &wnflag, 0))
+        if (newcompat.spe || newcompat.hs)
+            wnflag = 1;
+        else
+            wnflag = 0;
+
     *model = NULL;
 
     /* read W and L. If not on the instance line, leave */
     if (!parse_line(line, instance_tokens, 2, parse_values, parse_found))
         return NULL;
 
-    /* This is for reading nf. If not available, set to 1. Only in Spectre compatibility mode */
-    if (!newcompat.spe || !parse_line(line, instance_tokens, 3, parse_values, parse_found))
-        parse_values[2] = 1.;
+    /* This is for reading nf. If nf is not available, set to 1 if in HSPICE or Spectre compatibility mode */
+    if (!parse_line(line, instance_tokens, 3, parse_values, parse_found)) {
+        parse_values[2] = 1.; /* divisor */
+    }
+    /* This is for reading wnflag from instance. If it is not available, no change.
+       If instance wnflag == 0, set divisor to 1, else use instance nf */
+    else if (parse_line(line, instance_tokens, 4, parse_values, parse_found)) {
+        /* wnflag from instance overrules: no use of nf */
+        if (parse_values[3] == 0) {
+            parse_values[2] = 1.; /* divisor */
+        }
+    }
+    /* We do have nf, but no wnflag on the instance. Now it depends on the default
+       wnflag or on the .options wnflag */
+    else {
+        if (wnflag == 0)
+            parse_values[2] = 1.; /* divisor */
+    }
+
 
     l = parse_values[0] * scale;
     w = parse_values[1] / parse_values[2] * scale;