diff --git a/vvp/codes.h b/vvp/codes.h
index b9bb701b0..6ed230175 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 1.31 2001/06/30 21:07:26 steve Exp $"
+#ident "$Id: codes.h,v 1.32 2001/07/19 04:40:55 steve Exp $"
 #endif
 
 
@@ -46,6 +46,7 @@ extern bool of_CMPU(vthread_t thr, vvp_code_t code);
 extern bool of_CMPX(vthread_t thr, vvp_code_t code);
 extern bool of_CMPZ(vthread_t thr, vvp_code_t code);
 extern bool of_DELAY(vthread_t thr, vvp_code_t code);
+extern bool of_DELAYX(vthread_t thr, vvp_code_t code);
 extern bool of_DISABLE(vthread_t thr, vvp_code_t code);
 extern bool of_END(vthread_t thr, vvp_code_t code);
 extern bool of_FORK(vthread_t thr, vvp_code_t code);
@@ -136,6 +137,9 @@ extern vvp_code_t codespace_index(vvp_cpoint_t ptr);
 
 /*
  * $Log: codes.h,v $
+ * Revision 1.32  2001/07/19 04:40:55  steve
+ *  Add support for the delayx opcode.
+ *
  * Revision 1.31  2001/06/30 21:07:26  steve
  *  Support non-const right shift (unsigned).
  *
diff --git a/vvp/compile.cc b/vvp/compile.cc
index 85c2dc02a..a78fa7e40 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 1.87 2001/07/11 04:43:57 steve Exp $"
+#ident "$Id: compile.cc,v 1.88 2001/07/19 04:40:55 steve Exp $"
 #endif
 
 # include  "arith.h"
@@ -87,6 +87,7 @@ const static struct opcode_table_s opcode_table[] = {
       { "%cmp/x",  of_CMPX,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%cmp/z",  of_CMPZ,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%delay",  of_DELAY,  1,  {OA_NUMBER,   OA_NONE,     OA_NONE} },
+      { "%delayx", of_DELAYX, 1,  {OA_NUMBER,   OA_NONE,     OA_NONE} },
       { "%end",    of_END,    0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%inv",    of_INV,    2,  {OA_BIT1,     OA_BIT2,     OA_NONE} },
       { "%ix/add", of_IX_ADD, 2,  {OA_BIT1,     OA_NUMBER,   OA_NONE} },
@@ -1544,6 +1545,9 @@ vvp_ipoint_t debug_lookup_functor(const char*name)
 
 /*
  * $Log: compile.cc,v $
+ * Revision 1.88  2001/07/19 04:40:55  steve
+ *  Add support for the delayx opcode.
+ *
  * Revision 1.87  2001/07/11 04:43:57  steve
  *  support postpone of $systask parameters. (Stephan Boettcher)
  *
diff --git a/vvp/opcodes.txt b/vvp/opcodes.txt
index 720e1497a..9adf04099 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 1.25 2001/06/30 21:07:26 steve Exp $
+ *  $Id: opcodes.txt,v 1.26 2001/07/19 04:40:55 steve Exp $
  */
 
 
@@ -118,6 +118,12 @@ future to reschedule, and is >= 0. If the %delay is zero, then the
 thread yields the processor for another thread, but will be resumed in
 the current time step.
 
+* %delayx <idx>
+
+This is similar to the %delay opcode, except that the parameter
+selects an index register, which contains the actual delay. This
+supports run-time calculated delays.
+
 * %disable <scope-label>
 
 This instruction terminates threads that are part of a specific
diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index 6e6f1d8ff..de42f1a95 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 1.48 2001/07/04 04:57:10 steve Exp $"
+#ident "$Id: vthread.cc,v 1.49 2001/07/19 04:40:55 steve Exp $"
 #endif
 
 # include  "vthread.h"
@@ -539,6 +539,16 @@ bool of_DELAY(vthread_t thr, vvp_code_t cp)
       return false;
 }
 
+bool of_DELAYX(vthread_t thr, vvp_code_t cp)
+{
+      unsigned long delay;
+
+      assert(cp->number < 4);
+      delay = thr->index[cp->number];
+      schedule_vthread(thr, delay);
+      return false;
+}
+
 /*
  * Implement the %disable instruction by scanning the target scope for
  * all the target threads. Kill the target threads and wake up a
@@ -1281,6 +1291,9 @@ bool of_ZOMBIE(vthread_t thr, vvp_code_t)
 
 /*
  * $Log: vthread.cc,v $
+ * Revision 1.49  2001/07/19 04:40:55  steve
+ *  Add support for the delayx opcode.
+ *
  * Revision 1.48  2001/07/04 04:57:10  steve
  *  Relax limit on behavioral subtraction.
  *