diff --git a/tgt-vvp/eval_expr.c b/tgt-vvp/eval_expr.c
index ad865524c..04ec06260 100644
--- a/tgt-vvp/eval_expr.c
+++ b/tgt-vvp/eval_expr.c
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: eval_expr.c,v 1.59 2002/05/07 03:49:58 steve Exp $"
+#ident "$Id: eval_expr.c,v 1.60 2002/05/29 16:29:34 steve Exp $"
 #endif
 
 # include  "vvp_priv.h"
@@ -539,6 +539,45 @@ static struct vector_info draw_binary_expr_lrs(ivl_expr_t exp, unsigned wid)
       return lv;
 }
 
+static struct vector_info draw_add_immediate(ivl_expr_t le,
+					     ivl_expr_t re,
+					     unsigned wid)
+{
+      struct vector_info lv;
+      unsigned long imm = 0;
+      unsigned idx;
+
+      lv = draw_eval_expr_wid(le, wid);
+      assert(lv.wid == wid);
+
+      switch (ivl_expr_type(re)) {
+	  case IVL_EX_ULONG:
+	    imm = ivl_expr_uvalue(re);
+	    break;
+
+	  case IVL_EX_NUMBER: {
+		const char*bits = ivl_expr_bits(re);
+		unsigned nbits = ivl_expr_width(re);
+		for (idx = 0 ; idx < nbits ; idx += 1) switch (bits[idx]){
+		    case '0':
+		      break;
+		    case '1':
+		      imm |= 1 << idx;
+		      break;
+		    default:
+		      assert(0);
+		}
+		break;
+	  }
+
+	  default:
+	    assert(0);
+      }
+
+      assert(0 == (imm & ~0xffffUL));
+      fprintf(vvp_out, "    %%addi %u, %lu, %u;\n", lv.base, imm, wid);
+      return lv;
+}
 
 static struct vector_info draw_binary_expr_arith(ivl_expr_t exp, unsigned wid)
 {
@@ -550,6 +589,14 @@ static struct vector_info draw_binary_expr_arith(ivl_expr_t exp, unsigned wid)
 
       const char*sign_string = ivl_expr_signed(exp)? "/s" : "";
 
+      if ((ivl_expr_opcode(exp) == '+')
+	  && (ivl_expr_type(re) == IVL_EX_ULONG))
+	    return draw_add_immediate(le, re, wid);
+
+      if ((ivl_expr_opcode(exp) == '+')
+	  && (ivl_expr_type(re) == IVL_EX_NUMBER))
+	    return draw_add_immediate(le, re, wid);
+
       lv = draw_eval_expr_wid(le, wid);
       rv = draw_eval_expr_wid(re, wid);
 
@@ -1512,6 +1559,9 @@ struct vector_info draw_eval_expr(ivl_expr_t exp)
 
 /*
  * $Log: eval_expr.c,v $
+ * Revision 1.60  2002/05/29 16:29:34  steve
+ *  Add %addi, which is faster to simulate.
+ *
  * Revision 1.59  2002/05/07 03:49:58  steve
  *  Handle x case of unary ! properly.
  *
diff --git a/vvp/codes.h b/vvp/codes.h
index 3d0c44565..0b3838348 100644
--- a/vvp/codes.h
+++ b/vvp/codes.h
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: codes.h,v 1.40 2002/04/21 22:29:49 steve Exp $"
+#ident "$Id: codes.h,v 1.41 2002/05/29 16:29:34 steve Exp $"
 #endif
 
 
@@ -36,6 +36,7 @@ typedef bool (*vvp_code_fun)(vthread_t thr, vvp_code_t code);
  * access to the thread context.
  */
 extern bool of_ADD(vthread_t thr, vvp_code_t code);
+extern bool of_ADDI(vthread_t thr, vvp_code_t code);
 extern bool of_AND(vthread_t thr, vvp_code_t code);
 extern bool of_ANDR(vthread_t thr, vvp_code_t code);
 extern bool of_ASSIGN(vthread_t thr, vvp_code_t code);
@@ -153,6 +154,9 @@ extern vvp_code_t codespace_index(vvp_cpoint_t ptr);
 
 /*
  * $Log: codes.h,v $
+ * Revision 1.41  2002/05/29 16:29:34  steve
+ *  Add %addi, which is faster to simulate.
+ *
  * Revision 1.40  2002/04/21 22:29:49  steve
  *  Add the assign/d instruction for computed delays.
  *
diff --git a/vvp/compile.cc b/vvp/compile.cc
index 50d39cc43..794af114d 100644
--- a/vvp/compile.cc
+++ b/vvp/compile.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: compile.cc,v 1.127 2002/05/10 16:00:57 steve Exp $"
+#ident "$Id: compile.cc,v 1.128 2002/05/29 16:29:34 steve Exp $"
 #endif
 
 # include  "arith.h"
@@ -80,6 +80,7 @@ struct opcode_table_s {
 
 const static struct opcode_table_s opcode_table[] = {
       { "%add",    of_ADD,    3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
+      { "%addi",   of_ADDI,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%and",    of_AND,    3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%and/r",  of_ANDR,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%assign", of_ASSIGN, 3,  {OA_FUNC_PTR, OA_BIT1,     OA_BIT2} },
@@ -1411,6 +1412,9 @@ vvp_ipoint_t debug_lookup_functor(const char*name)
 
 /*
  * $Log: compile.cc,v $
+ * Revision 1.128  2002/05/29 16:29:34  steve
+ *  Add %addi, which is faster to simulate.
+ *
  * Revision 1.127  2002/05/10 16:00:57  steve
  *  Support scope iterate over vpiNet,vpiReg/vpiMemory.
  *
diff --git a/vvp/opcodes.txt b/vvp/opcodes.txt
index a38bc79e4..d15205bbf 100644
--- a/vvp/opcodes.txt
+++ b/vvp/opcodes.txt
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2001 Stephen Williams (steve@icarus.com)
  *
- *  $Id: opcodes.txt,v 1.34 2002/04/21 22:29:49 steve Exp $
+ *  $Id: opcodes.txt,v 1.35 2002/05/29 16:29:34 steve Exp $
  */
 
 
@@ -30,6 +30,12 @@ sum.
 
 See also the %sub instruction.
 
+* %addi <bit-l>, <imm>, <wid>
+
+This instruction adds the immediate value (no x or z bits) into the
+left vector. The imm value is limited to 16 significant bits, but it
+is zero extended to match any width.
+
 * %and <bit-l>, <bit-r>, <wid>
 
 Perform the bitwise AND of the two vectors, and store the result in
diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index 939f84cba..eaabf343a 100644
--- a/vvp/vthread.cc
+++ b/vvp/vthread.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: vthread.cc,v 1.73 2002/05/27 00:53:10 steve Exp $"
+#ident "$Id: vthread.cc,v 1.74 2002/05/29 16:29:34 steve Exp $"
 #endif
 
 # include  "vthread.h"
@@ -383,6 +383,64 @@ bool of_ADD(vthread_t thr, vvp_code_t cp)
       return true;
 }
 
+/*
+ * This is %addi, add-immediate. The first value is a vector, the
+ * second value is the immediate value in the bin_idx[1] position. The
+ * immediate value can be up to 16 bits, which are then padded to the
+ * width of the vector with zero.
+ */
+bool of_ADDI(vthread_t thr, vvp_code_t cp)
+{
+      assert(cp->bit_idx[0] >= 4);
+
+      unsigned word_count = (cp->number+CPU_BITS-1)/CPU_BITS;
+
+      unsigned long*lva = vector_to_array(thr, cp->bit_idx[0], cp->number);
+      unsigned long*lvb;
+      if (lva == 0)
+	    goto x_out;
+
+      lvb = new unsigned long[word_count];
+
+      lvb[0] = cp->bit_idx[1];
+      for (unsigned idx = 1 ;  idx < word_count ;  idx += 1)
+	    lvb[idx] = 0;
+
+      unsigned long carry;
+      carry = 0;
+      for (unsigned idx = 0 ;  (idx*CPU_BITS) < cp->number ;  idx += 1) {
+
+	    unsigned long tmp = lvb[idx] + carry;
+	    unsigned long sum = lva[idx] + tmp;
+	    carry = 0;
+	    if (tmp < lvb[idx])
+		  carry = 1;
+	    if (sum < tmp)
+		  carry = 1;
+	    if (sum < lva[idx])
+		  carry = 1;
+	    lva[idx] = sum;
+      }
+
+      for (unsigned idx = 0 ;  idx < cp->number ;  idx += 1) {
+	    unsigned bit = lva[idx/CPU_BITS] >> (idx % CPU_BITS);
+	    thr_put_bit(thr, cp->bit_idx[0]+idx, (bit&1) ? 1 : 0);
+      }
+
+      delete[]lva;
+      delete[]lvb;
+
+      return true;
+
+ x_out:
+      delete[]lva;
+
+      for (unsigned idx = 0 ;  idx < cp->number ;  idx += 1)
+	    thr_put_bit(thr, cp->bit_idx[0]+idx, 2);
+
+      return true;
+}
+
 bool of_ASSIGN(vthread_t thr, vvp_code_t cp)
 {
       unsigned char bit_val = thr_get_bit(thr, cp->bit_idx[1]);
@@ -1913,6 +1971,9 @@ bool of_CALL_UFUNC(vthread_t thr, vvp_code_t cp)
 
 /*
  * $Log: vthread.cc,v $
+ * Revision 1.74  2002/05/29 16:29:34  steve
+ *  Add %addi, which is faster to simulate.
+ *
  * Revision 1.73  2002/05/27 00:53:10  steve
  *  Able to disable thread self.
  *