Import code for article1, 2, 3, 4

1 files changed, 92 insertions, 0 deletions

diff --git a/sos-code-article4/hwcore/exception.c b/sos-code-article4/hwcore/exception.c
new file mode 100644
index 0000000..9ab5aff
--- /dev/null
+++ b/sos-code-article4/hwcore/exception.c
@@ -0,0 +1,92 @@
+/* Copyright (C) 2004  David Decotigny
+   Copyright (C) 1999  Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; either version 2
+   of the License, or (at your option) any later version.
+   
+   This program 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 General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   USA. 
+*/
+#include "idt.h"
+#include "irq.h"
+
+#include "exception.h"
+
+/* array of exception wrappers, defined in exception_wrappers.S */
+extern sos_vaddr_t sos_exception_wrapper_array[SOS_EXCEPT_NUM];
+
+/* arrays of exception handlers, shared with exception_wrappers.S */
+sos_exception_handler_t sos_exception_handler_array[SOS_EXCEPT_NUM] =
+  { NULL, };
+
+sos_ret_t sos_exceptions_setup(void)
+{
+  /* We inidicate that the double fault exception handler is defined,
+     and give its address. this handler is a do-nothing handler (see
+     exception_wrappers.S), and it can NOT be overriden by the
+     functions below */
+  return sos_idt_set_handler(SOS_EXCEPT_BASE + SOS_EXCEPT_DOUBLE_FAULT,
+			    (sos_vaddr_t) sos_exception_wrapper_array[SOS_EXCEPT_DOUBLE_FAULT],
+			    0 /* CPL0 routine */);
+}
+
+
+sos_ret_t sos_exception_set_routine(int exception_number,
+				    sos_exception_handler_t routine)
+{
+  sos_ret_t retval;
+  sos_ui32_t flags;
+  
+  if ((exception_number < 0) || (exception_number >= SOS_EXCEPT_NUM))
+    return -SOS_EINVAL;
+
+  /* Double fault not supported */
+  if (exception_number == SOS_EXCEPT_DOUBLE_FAULT)
+    return -SOS_ENOSUP;
+  
+  sos_disable_IRQs(flags);
+
+  retval = SOS_OK;
+
+  /* Set the exception routine to be called by the exception wrapper */
+  sos_exception_handler_array[exception_number] = routine;
+
+  /* If the exception is to be enabled, update the IDT with the exception
+     wrapper */
+  if (routine != NULL)
+    retval
+      = sos_idt_set_handler(SOS_EXCEPT_BASE + exception_number,
+			    (sos_vaddr_t) sos_exception_wrapper_array[exception_number],
+			    0 /* CPL0 routine */);
+  else /* Disable the IDT entry */
+    retval
+      = sos_idt_set_handler(SOS_EXCEPT_BASE + exception_number,
+			    (sos_vaddr_t)NULL /* No routine => disable IDTE */,
+			    0 /* don't care */);
+
+  sos_restore_IRQs(flags);
+  return retval;
+}
+
+
+sos_exception_handler_t sos_exception_get_routine(int exception_number)
+{
+  if ((exception_number < 0) || (exception_number >= SOS_EXCEPT_NUM))
+    return NULL;
+
+  /* Double fault not supported */
+  if (exception_number == SOS_EXCEPT_DOUBLE_FAULT)
+    return NULL;
+  
+  /* Expected to be atomic */
+  return sos_exception_handler_array[exception_number];
+}