target-or32: Add exception support

Add OpenRISC exception support.

Signed-off-by: Jia Liu <proljc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/target-openrisc/exception.c b/target-openrisc/exception.c
new file mode 100644
index 0000000..58e53c6
--- /dev/null
+++ b/target-openrisc/exception.c
@@ -0,0 +1,27 @@
+/*
+ * OpenRISC exception.
+ *
+ * Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "cpu.h"
+#include "exception.h"
+
+void QEMU_NORETURN raise_exception(OpenRISCCPU *cpu, uint32_t excp)
+{
+    cpu->env.exception_index = excp;
+    cpu_loop_exit(&cpu->env);
+}