diff --git a/Makefile.in b/Makefile.in
index fc291bf98..8b879a9cf 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -292,7 +292,7 @@ else
 WIN32_INSTALL = $(bindir)/iverilog-vpi$(suffix)
 endif
 
-install: all installdirs $(libdir)/ivl$(suffix)/ivl@EXEEXT@  $(libdir)/ivl$(suffix)/include/constants.vams $(libdir)/ivl$(suffix)/include/disciplines.vams $(includedir)/ivl_target.h $(includedir)/_pli_types.h $(includedir)/vpi_user.h $(includedir)/acc_user.h $(includedir)/veriuser.h $(WIN32_INSTALL) $(INSTALL_DOC)
+install: all installdirs $(libdir)/ivl$(suffix)/ivl@EXEEXT@  $(libdir)/ivl$(suffix)/include/constants.vams $(libdir)/ivl$(suffix)/include/disciplines.vams $(includedir)/ivl_target.h $(includedir)/_pli_types.h $(includedir)/sv_vpi_user.h $(includedir)/vpi_user.h $(includedir)/acc_user.h $(includedir)/veriuser.h $(WIN32_INSTALL) $(INSTALL_DOC)
 	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
 
 $(bindir)/iverilog-vpi$(suffix): ./iverilog-vpi
@@ -313,6 +313,9 @@ $(includedir)/ivl_target.h: $(srcdir)/ivl_target.h
 $(includedir)/_pli_types.h: _pli_types.h
 	$(INSTALL_DATA) $< "$(DESTDIR)$(includedir)/_pli_types.h"
 
+$(includedir)/sv_vpi_user.h: $(srcdir)/sv_vpi_user.h
+	$(INSTALL_DATA) $(srcdir)/sv_vpi_user.h "$(DESTDIR)$(includedir)/sv_vpi_user.h"
+
 $(includedir)/vpi_user.h: $(srcdir)/vpi_user.h
 	$(INSTALL_DATA) $(srcdir)/vpi_user.h "$(DESTDIR)$(includedir)/vpi_user.h"
 
diff --git a/vpi/sys_display.c b/vpi/sys_display.c
index 2ea8e830f..6069974e2 100644
--- a/vpi/sys_display.c
+++ b/vpi/sys_display.c
@@ -1047,6 +1047,10 @@ static int sys_check_args(vpiHandle callh, vpiHandle argv, const PLI_BYTE8*name,
 	      case vpiNet:
 	      case vpiReg:
 	      case vpiIntegerVar:
+	      case vpiByteVar:
+	      case vpiShortIntVar:
+	      case vpiIntVar:
+	      case vpiLongIntVar:
 	      case vpiTimeVar:
 	      case vpiRealVar:
 	      case vpiSysFuncCall:
diff --git a/vpi/sys_priv.h b/vpi/sys_priv.h
index 094416f28..f384cdef7 100644
--- a/vpi/sys_priv.h
+++ b/vpi/sys_priv.h
@@ -20,7 +20,7 @@
  */
 
 #include "vpi_config.h"
-#include "vpi_user.h"
+#include "sv_vpi_user.h"
 
 /*
  * Context structure for PRNG in mt19937int.c
diff --git a/vvp/README.txt b/vvp/README.txt
index 8e43030b5..817df5b67 100644
--- a/vvp/README.txt
+++ b/vvp/README.txt
@@ -278,8 +278,10 @@ A variable is a bit vector that can be written by behavioral code (so
 has no structural input) and propagates its output to a functor. The
 general syntax of a variable is:
 
-	<label> .var   "name", <msb>, <lsb>; Unsigned logic variable
-	<label> .var/s "name", <msb>, <lsb>; Signed logic variable
+	<label> .var   "name", <msb> <lsb>; Unsigned logic variable
+	<label> .var/s "name", <msb> <lsb>; Signed logic variable
+	<label> .var/2u "name", <msb> <lsb>; Unsigned bool/bit variable
+	<label> .var/2s "name", <msb> <lsb>; Signed bool/bit variable
 	<label> .var/real "name", <msb>, <lsb>; real varibale
 	<label> .var/i "name", <msb>, <lsb>; vpiIntegerVar variable
 
diff --git a/vvp/array.h b/vvp/array.h
index 6a4f83ed8..426439343 100644
--- a/vvp/array.h
+++ b/vvp/array.h
@@ -52,9 +52,6 @@ extern void vpip_array_word_change(struct __vpiCallback*cb, vpiHandle word);
 extern void vpip_array_change(struct __vpiCallback*cb, vpiHandle word);
 
 /* Compile hooks */
-extern void compile_variablew(char*label, vvp_array_t array,
-			      unsigned long array_addr,
-			     int msb, int lsb, char signed_flag);
 extern void compile_varw_real(char*label, vvp_array_t array,
 			      unsigned long array_addr,
 			      int msb, int lsb);
diff --git a/vvp/compile.cc b/vvp/compile.cc
index fb157a399..586ba9884 100644
--- a/vvp/compile.cc
+++ b/vvp/compile.cc
@@ -285,6 +285,10 @@ vvp_net_t* vvp_net_lookup(const char*label)
 	    switch (vpi->vpi_type->type_code) {
 		case vpiNet:
 		case vpiReg:
+		case vpiByteVar:
+		case vpiShortIntVar:
+		case vpiIntVar:
+		case vpiLongIntVar:
 		case vpiIntegerVar: {
 		      __vpiSignal*sig = (__vpiSignal*)vpi;
 		      return sig->node;
diff --git a/vvp/compile.h b/vvp/compile.h
index 57d1bf111..7b2d2d157 100644
--- a/vvp/compile.h
+++ b/vvp/compile.h
@@ -23,7 +23,7 @@
 # include  <fstream>
 # include  <vector>
 # include  "parse_misc.h"
-# include  "vpi_user.h"
+# include  "sv_vpi_user.h"
 # include  "vvp_net.h"
 
 using namespace std;
@@ -431,10 +431,15 @@ extern void compile_thread(char*start_sym, char*flag);
 
 /*
  * This function is called to create a var vector with the given name.
+ *
+ * The vpi_type_code argument of compile_variable() is one of the vpi
+ * object codes that identify the type: vpiReg, vpiIntegerVar,
+ * vpiIntVar, etc.
  */
 extern void compile_variable(char*label, char*name,
-			     int msb, int lsb, char signed_flag,
-			     bool local_flag);
+			     int msb, int lsb, int vpi_type_code,
+			     bool signed_flag, bool local_flag);
+
 extern void compile_var_real(char*label, char*name,
 			     int msb, int lsb);
 
diff --git a/vvp/lexor.lex b/vvp/lexor.lex
index e59210a5a..b9519b73f 100644
--- a/vvp/lexor.lex
+++ b/vvp/lexor.lex
@@ -188,6 +188,8 @@ static char* strdupnew(char const *str)
 ".var/real" { return K_VAR_R; }
 ".var/s"    { return K_VAR_S; }
 ".var/i"    { return K_VAR_I; /* integer */ }
+".var/2s"    { return K_VAR_2S; /* byte/shortint/int/longint signed */ }
+".var/2u"    { return K_VAR_2U; /* byte/shortint/int/longint unsigned */ }
 ".udp"         { return K_UDP; }
 ".udp/c"(omb)? { return K_UDP_C; }
 ".udp/s"(equ)? { return K_UDP_S; }
diff --git a/vvp/parse.y b/vvp/parse.y
index 274207098..2d2d29655 100644
--- a/vvp/parse.y
+++ b/vvp/parse.y
@@ -84,7 +84,8 @@ static struct __vpiModPath*modpath_dst = 0;
 %token K_RESOLV K_SCOPE K_SFUNC K_SFUNC_E K_SHIFTL K_SHIFTR K_SHIFTRS
 %token K_THREAD K_TIMESCALE K_TRAN K_TRANIF0 K_TRANIF1 K_TRANVP
 %token K_UFUNC K_UFUNC_E K_UDP K_UDP_C K_UDP_S
-%token K_VAR K_VAR_S K_VAR_I K_VAR_R K_vpi_call K_vpi_call_w K_vpi_call_i
+%token K_VAR K_VAR_S K_VAR_I K_VAR_R K_VAR_2S K_VAR_2U
+%token K_vpi_call K_vpi_call_w K_vpi_call_i
 %token K_vpi_func K_vpi_func_r
 %token K_disable K_fork
 %token K_ivl_version K_ivl_delay_selection
@@ -650,13 +651,19 @@ statement
      the variable in the netlist. */
 
   | T_LABEL K_VAR local_flag T_STRING ',' signed_t_number signed_t_number ';'
-      { compile_variable($1, $4, $6, $7, 0 /* unsigned */, $3); }
+      { compile_variable($1, $4, $6, $7, vpiLogicVar, false, $3); }
 
   | T_LABEL K_VAR_S local_flag T_STRING ',' signed_t_number signed_t_number ';'
-      { compile_variable($1, $4, $6, $7, 1 /* signed */, $3); }
+      { compile_variable($1, $4, $6, $7, vpiLogicVar, true, $3); }
 
   | T_LABEL K_VAR_I local_flag T_STRING ',' T_NUMBER T_NUMBER ';'
-      { compile_variable($1, $4, $6, $7, 2 /* integer */, $3); }
+      { compile_variable($1, $4, $6, $7, vpiIntegerVar, true, $3); }
+
+  | T_LABEL K_VAR_2S local_flag T_STRING ',' T_NUMBER T_NUMBER ';'
+      { compile_variable($1, $4, $6, $7, vpiIntVar, true, $3); }
+
+  | T_LABEL K_VAR_2U local_flag T_STRING ',' T_NUMBER T_NUMBER ';'
+      { compile_variable($1, $4, $6, $7, vpiIntVar, false, $3); }
 
   | T_LABEL K_VAR_R T_STRING ',' signed_t_number signed_t_number ';'
       { compile_var_real($1, $3, $5, $6); }
diff --git a/vvp/vpi_priv.cc b/vvp/vpi_priv.cc
index 3a2e88fad..ac729265a 100644
--- a/vvp/vpi_priv.cc
+++ b/vvp/vpi_priv.cc
@@ -255,14 +255,20 @@ static const char* vpi_type_values(PLI_INT32 code)
 {
       static char buf[32];
       switch (code) {
+	  case vpiByteVar:
+	    return "vpiByteVar";
 	  case vpiConstant:
 	    return "vpiConstant";
 	  case vpiFunction:
 	    return "vpiFunction";
+	  case vpiIntVar:
+	    return "vpiIntVar";
 	  case vpiIntegerVar:
 	    return "vpiIntegerVar";
 	  case vpiIterator:
 	    return "vpiIterator";
+	  case vpiLongIntVar:
+	    return "vpiLongIntVar";
 	  case vpiMemory:
 	    return "vpiMemory";
 	  case vpiMemoryWord:
@@ -287,6 +293,8 @@ static const char* vpi_type_values(PLI_INT32 code)
 	    return "vpiRealVar";
 	  case vpiReg:
 	    return "vpiReg";
+	  case vpiShortIntVar:
+	    return "vpiShortIntVar";
 	  case vpiSysFuncCall:
 	    return "vpiSysFuncCall";
 	  case vpiSysTaskCall:
@@ -318,9 +326,7 @@ PLI_INT32 vpi_get(int property, vpiHandle ref)
 	    }
 
 	    struct __vpiSignal*rfp = (struct __vpiSignal*)ref;
-	    if (ref->vpi_type->type_code == vpiReg && rfp->isint_)
-		  return vpiIntegerVar;
-	    else if (ref->vpi_type->type_code == vpiMemory && is_net_array(ref))
+	    if (ref->vpi_type->type_code == vpiMemory && is_net_array(ref))
 		  return vpiNetArray;
 	    else
 		  return ref->vpi_type->type_code;
@@ -375,9 +381,7 @@ char* vpi_get_str(PLI_INT32 property, vpiHandle ref)
 
 	    struct __vpiSignal*rfp = (struct __vpiSignal*)ref;
             PLI_INT32 type;
-	    if (ref->vpi_type->type_code == vpiReg && rfp->isint_)
-		  type = vpiIntegerVar;
-	    else if (ref->vpi_type->type_code == vpiMemory && is_net_array(ref))
+	    if (ref->vpi_type->type_code == vpiMemory && is_net_array(ref))
 		  type = vpiNetArray;
 	    else
 		  type = ref->vpi_type->type_code;
diff --git a/vvp/vpi_priv.h b/vvp/vpi_priv.h
index cda40dbf6..f4dc4f67a 100644
--- a/vvp/vpi_priv.h
+++ b/vvp/vpi_priv.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 
-# include  "vpi_user.h"
+# include  "sv_vpi_user.h"
 # include  "vvp_net.h"
 # include  "config.h"
 
@@ -243,7 +243,6 @@ struct __vpiSignal {
       int msb, lsb;
 	/* Flags */
       unsigned signed_flag  : 1;
-      unsigned isint_       : 1; // original type was integer
       unsigned is_netarray  : 1; // This is word of a net array
 	/* The represented value is here. */
       vvp_net_t*node;
@@ -251,12 +250,14 @@ struct __vpiSignal {
 extern unsigned vpip_size(__vpiSignal *sig);
 extern struct __vpiScope* vpip_scope(__vpiSignal*sig);
 
-extern vpiHandle vpip_make_int(const char*name, int msb, int lsb,
+extern vpiHandle vpip_make_int2(const char*name, int msb, int lsb,
 			       vvp_net_t*vec);
-extern vpiHandle vpip_make_reg(const char*name, int msb, int lsb,
+extern vpiHandle vpip_make_int4(const char*name, int msb, int lsb,
+			       vvp_net_t*vec);
+extern vpiHandle vpip_make_var4(const char*name, int msb, int lsb,
 			       bool signed_flag, vvp_net_t*net);
-extern vpiHandle vpip_make_net(const char*name, int msb, int lsb,
-			       bool signed_flag, vvp_net_t*node);
+extern vpiHandle vpip_make_net4(const char*name, int msb, int lsb,
+				bool signed_flag, vvp_net_t*node);
 
 /*
  * This is used by system calls to represent a bit/part select of
diff --git a/vvp/vpi_signal.cc b/vvp/vpi_signal.cc
index 0ff68bf03..2ea1a6573 100644
--- a/vvp/vpi_signal.cc
+++ b/vvp/vpi_signal.cc
@@ -506,11 +506,19 @@ static void format_vpiVectorVal(vvp_signal_value*sig, int base, unsigned wid,
 
 struct __vpiSignal* vpip_signal_from_handle(vpiHandle ref)
 {
-      if ((ref->vpi_type->type_code != vpiNet)
-	  && (ref->vpi_type->type_code != vpiReg))
-	    return 0;
+      switch (ref->vpi_type->type_code) {
+	  case vpiNet:
+	  case vpiReg:
+	  case vpiIntegerVar:
+	  case vpiByteVar:
+	  case vpiShortIntVar:
+	  case vpiIntVar:
+	  case vpiLongIntVar:
+	    return (struct __vpiSignal*)ref;
 
-      return (struct __vpiSignal*)ref;
+	  default:
+	    return 0;
+      }
 }
 
 /*
@@ -870,6 +878,17 @@ static const struct __vpirt vpip_reg_rt = {
       0
 };
 
+static const struct __vpirt vpip_integer_rt = {
+      vpiIntegerVar,
+      signal_get,
+      signal_get_str,
+      signal_get_value,
+      signal_put_value,
+      signal_get_handle,
+      signal_iterate,
+      0
+};
+
 static const struct __vpirt vpip_net_rt = {
       vpiNet,
       signal_get,
@@ -881,31 +900,97 @@ static const struct __vpirt vpip_net_rt = {
       0
 };
 
+static const struct __vpirt vpip_byte_rt = {
+      vpiByteVar,
+      signal_get,
+      signal_get_str,
+      signal_get_value,
+      signal_put_value,
+      signal_get_handle,
+      signal_iterate,
+      0
+};
+
+static const struct __vpirt vpip_shortint_rt = {
+      vpiShortIntVar,
+      signal_get,
+      signal_get_str,
+      signal_get_value,
+      signal_put_value,
+      signal_get_handle,
+      signal_iterate,
+      0
+};
+
+static const struct __vpirt vpip_int_rt = {
+      vpiIntVar,
+      signal_get,
+      signal_get_str,
+      signal_get_value,
+      signal_put_value,
+      signal_get_handle,
+      signal_iterate,
+      0
+};
+
+static const struct __vpirt vpip_longint_rt = {
+      vpiLongIntVar,
+      signal_get,
+      signal_get_str,
+      signal_get_value,
+      signal_put_value,
+      signal_get_handle,
+      signal_iterate,
+      0
+};
+
 
 /*
  * Construct a vpiIntegerVar object. Indicate the type using a flag
  * to minimize the code modifications. Icarus implements integers
  * as 'reg signed [31:0]'.
  */
-vpiHandle vpip_make_int(const char*name, int msb, int lsb, vvp_net_t*vec)
+vpiHandle vpip_make_int4(const char*name, int msb, int lsb, vvp_net_t*vec)
 {
-      vpiHandle obj = vpip_make_net(name, msb,lsb, true, vec);
-      struct __vpiSignal*rfp = (struct __vpiSignal*)obj;
-      obj->vpi_type = &vpip_reg_rt;
-      rfp->isint_ = true;
+      vpiHandle obj = vpip_make_net4(name, msb,lsb, true, vec);
+      obj->vpi_type = &vpip_integer_rt;
+      return obj;
+}
+
+vpiHandle vpip_make_int2(const char*name, int msb, int lsb, vvp_net_t*vec)
+{
+      vpiHandle obj = vpip_make_net4(name, msb,lsb, true, vec);
+
+      assert(lsb == 0);
+      switch (msb) {
+	  case 7:
+	    obj->vpi_type = &vpip_byte_rt;
+	    break;
+	  case 15:
+	    obj->vpi_type = &vpip_shortint_rt;
+	    break;
+	  case 31:
+	    obj->vpi_type = &vpip_int_rt;
+	    break;
+	  case 63:
+	    obj->vpi_type = &vpip_longint_rt;
+	    break;
+      }
+
       return obj;
 }
 
 /*
- * Construct a vpiReg object. It's like a net, except for the type.
+ * Construct a vpiReg/vpiLogicVar object. It's like a net, except for the type.
  */
-vpiHandle vpip_make_reg(const char*name, int msb, int lsb,
+vpiHandle vpip_make_var4(const char*name, int msb, int lsb,
 			bool signed_flag, vvp_net_t*vec)
 {
-      vpiHandle obj = vpip_make_net(name, msb,lsb, signed_flag, vec);
+      vpiHandle obj = vpip_make_net4(name, msb,lsb, signed_flag, vec);
       obj->vpi_type = &vpip_reg_rt;
       return obj;
 }
+
 #ifdef CHECK_WITH_VALGRIND
 static struct __vpiSignal **signal_pool = 0;
 static unsigned signal_pool_count = 0;
@@ -981,7 +1066,7 @@ void signal_pool_delete()
  * The name is the PLI name for the object. If it is an array it is
  * <name>[<index>].
  */
-vpiHandle vpip_make_net(const char*name, int msb, int lsb,
+vpiHandle vpip_make_net4(const char*name, int msb, int lsb,
 			bool signed_flag, vvp_net_t*node)
 {
       struct __vpiSignal*obj = allocate_vpiSignal();
@@ -990,7 +1075,6 @@ vpiHandle vpip_make_net(const char*name, int msb, int lsb,
       obj->msb = msb;
       obj->lsb = lsb;
       obj->signed_flag = signed_flag? 1 : 0;
-      obj->isint_ = 0;
       obj->is_netarray = 0;
       obj->node = node;
 
diff --git a/vvp/words.cc b/vvp/words.cc
index 1236547c9..afdfe4bea 100644
--- a/vvp/words.cc
+++ b/vvp/words.cc
@@ -84,7 +84,8 @@ void compile_varw_real(char*label, vvp_array_t array,
  */
 static void __compile_var(char*label, char*name,
 			  vvp_array_t array, unsigned long array_addr,
-			  int msb, int lsb, char signed_flag, bool local_flag)
+			  int msb, int lsb, int vpi_type_code,
+			  bool signed_flag, bool local_flag)
 {
       unsigned wid = ((msb > lsb)? msb-lsb : lsb-msb) + 1;
 
@@ -105,9 +106,21 @@ static void __compile_var(char*label, char*name,
       vpiHandle obj = 0;
       if (! local_flag && !array) {
 	      /* Make the vpiHandle for the reg. */
-	    obj = (signed_flag > 1) ?
-		  vpip_make_int(name, msb, lsb, net) :
-		  vpip_make_reg(name, msb, lsb, signed_flag!=0, net);
+	    switch (vpi_type_code) {
+		case vpiLogicVar:
+		  obj = vpip_make_var4(name, msb, lsb, signed_flag, net);
+		  break;
+		case vpiIntegerVar:
+		  obj = vpip_make_int4(name, msb, lsb, net);
+		  break;
+		case vpiIntVar: // This handles all the atom2 int types
+		  obj = vpip_make_int2(name, msb, lsb, net);
+		  break;
+		default:
+		  fprintf(stderr, "internal error: %s: vpi_type_code=%d\n", name, vpi_type_code);
+		  break;
+	    }
+	    assert(obj);
 	    compile_vpi_symbol(label, obj);
       }
 	// If the signal has a name, then it goes into the current
@@ -132,24 +145,10 @@ static void __compile_var(char*label, char*name,
 }
 
 void compile_variable(char*label, char*name,
-		      int msb, int lsb, char signed_flag, bool local_flag)
+		      int msb, int lsb, int vpi_type_code,
+		      bool signed_flag, bool local_flag)
 {
-      __compile_var(label, name, 0, 0, msb, lsb, signed_flag, local_flag);
-}
-
-/*
-* In this case, the variable it intended to be attached to the array
-* as a word. The array_addr is the *canonical* address of the word in
-* the array.
-*
-* This function is actually used by the compile_array function,
-* instead of directly by the parser.
-*/
-void compile_variablew(char*label, vvp_array_t array,
-		       unsigned long array_addr,
-		       int msb, int lsb, char signed_flag)
-{
-      __compile_var(label, 0, array, array_addr, msb, lsb, signed_flag, false);
+      __compile_var(label, name, 0, 0, msb, lsb, vpi_type_code, signed_flag, local_flag);
 }
 
 vvp_net_t* create_constant_node(const char*label, const char*val_str)
@@ -238,7 +237,7 @@ class __compile_net_resolv : public base_net_resolv {
  * references into the net.
  */
 
-static void __compile_net2(vvp_net_t*node, vvp_array_t array,
+static void do_compile_net(vvp_net_t*node, vvp_array_t array,
 			   struct __vpiScope*scope,
 			   char*my_label, char*name,
 			   int msb, int lsb, unsigned array_addr,
@@ -260,7 +259,7 @@ static void __compile_net2(vvp_net_t*node, vvp_array_t array,
       vpiHandle obj = 0;
       if (! local_flag) {
 	      /* Make the vpiHandle for the reg. */
-	    obj = vpip_make_net(name, msb, lsb, signed_flag, node);
+	    obj = vpip_make_net4(name, msb, lsb, signed_flag, node);
 	      /* This attaches the label to the vpiHandle */
 	    compile_vpi_symbol(my_label, obj);
       }
@@ -321,7 +320,7 @@ static void __compile_net(char*label,
       assert(node);
 
       struct __vpiScope*scope = vpip_peek_current_scope();
-      __compile_net2(node, array, scope, label, name, msb, lsb, array_addr,
+      do_compile_net(node, array, scope, label, name, msb, lsb, array_addr,
 		     signed_flag, net8_flag, local_flag);
 
       free(argv[0].text);
@@ -335,7 +334,7 @@ bool __compile_net_resolv::resolve(bool msg_flag)
 	    return false;
       }
 
-      __compile_net2(node, array_, scope_, my_label_, name_, msb_, lsb_, array_addr_, signed_flag_, net8_flag_, local_flag_);
+      do_compile_net(node, array_, scope_, my_label_, name_, msb_, lsb_, array_addr_, signed_flag_, net8_flag_, local_flag_);
       return true;
 }