new file mode 100644
--- /dev/null
+++ b/packages/hal/synth/arch/current/include/hal_cache.h
@@ -0,0 +1,69 @@
+#ifndef CYGONCE_HAL_CACHE_H
+#define CYGONCE_HAL_CACHE_H
+
+//=============================================================================
+//
+//      hal_cache.h
+//
+//      HAL cache control API
+//
+//=============================================================================
+//####COPYRIGHTBEGIN####
+//                                                                          
+// -------------------------------------------                              
+// The contents of this file are subject to the Red Hat eCos Public License 
+// Version 1.1 (the "License"); you may not use this file except in         
+// compliance with the License.  You may obtain a copy of the License at    
+// http://www.redhat.com/                                                   
+//                                                                          
+// 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 Configurable Operating System,      
+// released September 30, 1998.                                             
+//                                                                          
+// The Initial Developer of the Original Code is Red Hat.                   
+// Portions created by Red Hat are                                          
+// Copyright (C) 1998, 1999, 2000, 2001 Red Hat, Inc.                             
+// All Rights Reserved.                                                     
+// -------------------------------------------                              
+//                                                                          
+//####COPYRIGHTEND####
+//=============================================================================
+//#####DESCRIPTIONBEGIN####
+//
+// Author(s):   nickg
+// Contributors:proven,bartv
+// Date:        1998-10-29
+// Purpose:     Cache control API
+// Description: The macros defined here provide the HAL APIs for handling
+//              cache control operations.
+// Usage:
+//              #include <cyg/hal/hal_cache.h>
+//              ...
+//
+//####DESCRIPTIONEND####
+//
+//=============================================================================
+
+// ----------------------------------------------------------------------------
+// The synthetic target does not have a cache. The underlying hardware
+// is quite likely to have a cache, but the synthetic target code has
+// no way of manipulating it. A minimal set of no-op #define's is
+// required.
+
+#define HAL_ICACHE_ENABLE()
+#define HAL_ICACHE_DISABLE()
+#define HAL_ICACHE_SYNC()
+#define HAL_ICACHE_INVALIDATE_ALL()
+
+#define HAL_DCACHE_ENABLE()
+#define HAL_DCACHE_DISABLE()
+#define HAL_DCACHE_SYNC()
+#define HAL_DCACHE_INVALIDATE_ALL()
+
+//-----------------------------------------------------------------------------
+#endif // ifndef CYGONCE_HAL_CACHE_H
+// End of hal_cache.h