/* 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];
 }