move sboot to the root directory

[open-ath9k-htc-firmware.git] / sboot / magpie_1_1 / sboot / athos / src / xtos / exc-syscall-c-handler.c

diff --git a/sboot/magpie_1_1/sboot/athos/src/xtos/exc-syscall-c-handler.c b/sboot/magpie_1_1/sboot/athos/src/xtos/exc-syscall-c-handler.c
new file mode 100755 (executable)
index 0000000..405f7b6
--- /dev/null
+++ b/sboot/magpie_1_1/sboot/athos/src/xtos/exc-syscall-c-handler.c
@@ -0,0 +1,101 @@
+/* exc-syscall-c-handler.c - SYSCALL instruction XTOS handler in C */
+
+/*
+ * Copyright (c) 1999-2006 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.
+ */
+
+#include <xtensa/config/core.h>
+#include "xtos-internal.h"
+
+
+/*
+ *  User vector mode exception handler for the SYSCALL cause.
+ *
+ *  NOTE:  This function is NOT used by default.  The assembly-level
+ *  handler version of this function is normally used instead.
+ *  This function is provided as an example only.
+ *  To use it instead of the default assembly-level version,
+ *  you can register it using _xtos_set_exception_handler().
+ *  For example:
+ *
+ *     #include <xtensa/xtruntime.h>
+ *     #include <xtensa/corebits.h>
+ *     _xtos_set_exception_handler( EXCCAUSE_SYSCALL,
+ *                     (_xtos_handler)_xtos_p_syscall_handler );
+ */
+UserFrame* _xtos_p_syscall_handler( UserFrame *uf /*, int cause */ )
+{
+    uf->pc += 3;       /* skip SYSCALL instruction */
+
+#if XCHAL_HAVE_LOOPS
+    /*
+     *  If the SYSCALL instruction was the last instruction in the body
+     *  of a zero-overhead loop, then we should decrement the loop count
+     *  and resume execution at the head of the loop.
+     */
+
+    if( uf->pc == uf->lend && uf->lcount != 0 )
+    {
+       uf->lcount--;
+       uf->pc = uf->lbeg;
+    }
+#endif /*XCHAL_HAVE_LOOP*/
+
+    /*
+     *  Handle the system call.
+     *
+     *  A typical SYSCALL handler uses code such as this to handle
+     *  the system call, where the operation to be done is determined
+     *  by the a2 register.  Parameters to the operation are typically
+     *  passed in address registers a3 and up.  Results are typically
+     *  returned in a2.  (See Linux source code for example.)
+     */
+    switch( uf->a2 ) {
+       case 0:
+           /*  Spill register windows to the stack.  */
+           /*
+            *  The Xtensa architecture reserves the a2==0 condition as a request
+            *  to flush (spill) register windows to the stack.  The current exception
+            *  handling implementation never spills windows to the stack (it used
+            *  to always spill, not true anymore), so we have to spill windows
+            *  explicitly here.  (Note that xthal_window_spill() spills windows
+            *  that are part of the interrupt handling context, that don't
+            *  really need to be spilled, but that's harmless other than being
+            *  less than optimally efficient.)
+            *
+            *  Also, be nice to programmers here.  If they're
+            *  building for Call0 ABI, silently do nothing for
+            *  syscall a2==0.
+            */
+#ifdef __XTENSA_WINDOWED_ABI__
+           xthal_window_spill();
+#endif
+           break;
+
+       default:
+           uf->a2 = -1 /*ENOSYS*/;     /* system call not supported */
+           break;
+    }
+
+    return( uf );
+}
+