--- /dev/null
+// null-syscall.S - Stub for Unused SYSCALL Handler
+// $Id: //depot/rel/Cottonwood/Xtensa/OS/xtos/null-syscall.S#3 $
+
+// Copyright (c) 2006-2010 Tensilica Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+ // Redirect SYSCALL exceptions as not handled, when
+ // that functionality is not needed. Done this way, a user can
+ // just specify this small handler to override the default one.
+
+ .text
+ .weak _xtos_unhandled_exception
+ .global _xtos_syscall_handler
+_xtos_syscall_handler:
+ movi a3, _xtos_unhandled_exception
+1: beqz a3, 1b
+ jx a3
+ .size _xtos_syscall_handler, . - _xtos_syscall_handler
+