new file mode 100644
--- /dev/null
+++ b/packages/kernel/current/src/debug/dbg-thread-demux.c
@@ -0,0 +1,160 @@
+/*==========================================================================
+//
+//      dbg-thread-demux.c
+//
+//      GDB Stub ROM system calls
+//
+//==========================================================================
+//####COPYRIGHTBEGIN####
+//
+// -------------------------------------------
+// The contents of this file are subject to the Cygnus eCos Public License
+// Version 1.0 (the "License"); you may not use this file except in
+// compliance with the License.  You may obtain a copy of the License at
+// http://sourceware.cygnus.com/ecos
+// 
+// Software distributed under the License is distributed on an "AS IS"
+// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
+// License for the specific language governing rights and limitations under
+// the License.
+// 
+// The Original Code is eCos - Embedded Cygnus Operating System, released
+// September 30, 1998.
+// 
+// The Initial Developer of the Original Code is Cygnus.  Portions created
+// by Cygnus are Copyright (C) 1998 Cygnus Solutions.  All Rights Reserved.
+// -------------------------------------------
+//
+//####COPYRIGHTEND####
+//==========================================================================
+//#####DESCRIPTIONBEGIN####
+//
+// Author(s):   nickg
+// Contributors: 
+// Date:        1998-09-03
+// Purpose:     GDB Stub ROM system calls
+// Description: 
+//
+//####DESCRIPTIONEND####
+//
+//========================================================================*/
+
+
+/* This file implements system calls out from the ROM debug stub into
+   the operating environment.
+   We assume they exist in the same address space.
+   This file should be linked into your operating environment, your O.S.
+   or whatever is managing multiple saved process contexts.
+   Your O.S. needs to implement and provide
+      dbg_thread_capabilities
+      dbg_currthread
+      dbg_threadlist
+      dbg_threadinfo
+      dbg_getthreadreg
+      dbg_setthreadreg
+
+   The debug stub will call this function by calling it indirectly
+   vis a pre-assigned location possably somthing like a virtual vector table.
+   Where this is exactly is platform specific.
+
+   The O.S. should call patch_dbg_syscalls() and pass the address of the
+   location to be patched with the dbg_thread_syscall_rmt function.
+   Nothing really calls this by name.
+
+   This scheme would also work if we wanted to use a real trapped system call.
+   */
+
+// -------------------------------------------------------------------------
+
+#include <pkgconf/kernel.h>
+
+#include "cyg/hal/dbg-threads-api.h"
+#include "dbg-thread-syscall.h" 
+
+// -------------------------------------------------------------------------
+
+static int dbg_thread_syscall_rmt(
+		       enum dbg_syscall_ids id,
+		       union dbg_thread_syscall_parms * p
+		       )
+{
+  switch (id)
+    {
+    case dbg_null_func : return 1 ;  /* test the syscall apparatus */
+
+#ifdef CYGDBG_KERNEL_DEBUG_GDB_THREAD_SUPPORT
+    case dbg_capabilities_func :
+      return dbg_thread_capabilities(p->cap_parms.abilities) ;
+      break ;
+    case dbg_currthread_func :
+      return dbg_currthread(p->currthread_parms.ref) ;
+      break ;
+    case dbg_threadlist_func :
+      return dbg_threadlist(p->threadlist_parms.startflag,
+			    p->threadlist_parms.lastid,
+			    p->threadlist_parms.nextthreadid) ;
+      break ;
+    case dbg_threadinfo_func :
+      return dbg_threadinfo(p->info_parms.ref,
+			    p->info_parms.info
+			    ) ;
+      break ;
+    case dbg_getthreadreg_func :
+      return dbg_getthreadreg(p->reg_parms.thread,
+			      p->reg_parms.regcount,
+			      p->reg_parms.registers) ;
+      break ;
+    case dbg_setthreadreg_func :
+      return dbg_setthreadreg(p->reg_parms.thread,
+			      p->reg_parms.regcount,
+			      p->reg_parms.registers) ;
+      break ;
+#endif /* CYGDBG_KERNEL_DEBUG_GDB_THREAD_SUPPORT */      
+    default :
+      return 0 ;  /* failure tue to non-implementation */
+    }
+}
+
+// -------------------------------------------------------------------------
+// When Cygmon calls us on the TX39 It has its own value in GP. We need to
+// save that and set our own before proceeding.
+
+#ifdef CYG_HAL_TX39
+static int dbg_thread_syscall_rmt_1(
+		       enum dbg_syscall_ids id,
+		       union dbg_thread_syscall_parms * p
+		       )
+{
+
+  register long gp_save;
+  int r;
+  asm ( "move   %0,$28;"
+        ".extern _gp;"
+        "la     $gp,_gp;"
+        : "=r"(gp_save)
+      );
+
+  r = dbg_thread_syscall_rmt( id, p );
+  
+  asm ( "move   $gp,%0;" :: "r"(gp_save) );
+
+  return r;
+  
+}
+#endif  
+
+// -------------------------------------------------------------------------
+
+void patch_dbg_syscalls(void * vector)
+{
+   dbg_syscall_func * f ;
+   f = vector ;
+#ifdef CYG_HAL_TX39
+   *f = dbg_thread_syscall_rmt_1 ;
+#else   
+   *f = dbg_thread_syscall_rmt ;
+#endif   
+}
+
+// -------------------------------------------------------------------------
+// End of dbg-thread-demux.c