src/spicelib/parse, implement `nint()' (`B' language)

src/include/ngspice/inpptree.h

@@ -128,6 +128,7 @@ void INPptPrint(char *str, IFparseTree * ptree);
 #define PTF_MAX	33
 #define PTF_CEIL	34
 #define PTF_FLOOR	35
+#define PTF_NINT	36
 
 /* The following things are used by the parser -- these are the token types the
  * lexer returns.

src/spicelib/parser/inpptree.c

@@ -156,6 +156,7 @@ static struct func {
     { "uramp",  PTF_URAMP,  (void(*)(void)) PTuramp } ,
     { "ceil",   PTF_CEIL,   (void(*)(void)) PTceil } ,
     { "floor",  PTF_FLOOR,  (void(*)(void)) PTfloor } ,
+    { "nint",   PTF_NINT,   (void(*)(void)) PTnint } ,
     { "-",      PTF_UMINUS, (void(*)(void)) PTuminus },
     /* MW. cif function added */
     { "u2",     PTF_USTEP2, (void(*)(void)) PTustep2},
@@ -491,6 +492,10 @@ static INPparseNode *PTdifferentiate(INPparseNode * p, int varnum)
             arg1 = mkcon(0.0);
             break;
 
+        case PTF_NINT:                /* naive: D(nint(u)) = 0 */
+            arg1 = mkcon(0.0);
+            break;
+
 
             /* MW. PTF_CIF for new cif function */
         case PTF_USTEP2: /* ustep2=uramp(x)-uramp(x-1) ustep2'=ustep(x)-ustep(x-1) */

src/spicelib/parser/inpxx.h

@@ -76,5 +76,6 @@ double PTge0(double arg);
 double PTle0(double arg);
 double PTceil(double arg);
 double PTfloor(double arg);
+double PTnint(double arg);
 
 #endif

src/spicelib/parser/ptfuncs.c

@@ -339,3 +339,12 @@ PTfloor(double arg1)
     return (floor(arg1));
 }
 
+double
+PTnint(double arg1)
+{
+    /* round to "nearest integer",
+     *   round half-integers to the nearest even integer
+     *   rely on default rounding mode of IEEE 754 to do so
+     */
+    return nearbyint(arg1);
+}