/* Copyright (C) 2004  David Decotigny
 
    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. 
 */
 #ifndef _SOS_IDT_H_
 #define _SOS_IDT_H_
 
 /**
  * @file idt.h
  *
  * Manage the x86 Interrupt Descriptor Table, the table which maps the
  * hardware interrupt lines, hardware exceptions, and software
  * interrupts, to software routines. We only define "interrupt gate"
  * IDT entries. Don't use it directly; refer instead to interrupt.c,
  * exceptions.c and syscall.c.
  *
  * @see Intel x86 doc, Vol 3, chapter 5
  */
 
 #include <sos/errno.h>
 #include <sos/types.h>
 
 /* Mapping of the CPU exceptions in the IDT (imposed by Intel
    standards) */
 #define SOS_EXCEPT_BASE 0
 #define SOS_EXCEPT_NUM  32
 #define SOS_EXCEPT_MAX  (SOS_HWEXCEPT_BASE + SOS_HWEXCEPT_NUM - 1)
 
 /* Mapping of the IRQ lines in the IDT */
 #define SOS_IRQ_BASE    32
 #define SOS_IRQ_NUM     16
 #define SOS_IRQ_MAX     (SOS_IRQ_BASE + SOS_IRQ_NUM - 1)
 
 /**
  * Number of IDT entries.
  *
  * @note Must be large enough to map the hw interrupts, the exceptions
  * (=> total is 48 entries), and the syscall(s). Since our syscall
  * will be 0x42, it must be >= 0x43. Intel doc limits this to 256
  * entries, we use this limit.
  */
 #define SOS_IDTE_NUM      256 /* 0x100 */
 
 /** Initialization routine: all the IDT entries (or "IDTE") are marked
     "not present". */
 sos_ret_t sos_idt_subsystem_setup(void);
 
 /**
  * Enable the IDT entry if handler_address != NULL, with the given
  * lowest_priviledge.\ Disable the IDT entry when handler_address ==
  * NULL (the lowest_priviledge parameter is then ignored). Intel doc
  * says that there must not be more than 256 entries.
  *
  * @note IRQ Unsafe
  */
 sos_ret_t sos_idt_set_handler(int index,
                               sos_vaddr_t handler_address,
                               int lowest_priviledge /* 0..3 */);
 
 
 /**
  * @note IRQ Unsafe
  *
  * @return the handler address and DPL in the 2nd and 3rd
  * parameters
  */
 sos_ret_t sos_idt_get_handler(int index,
                               sos_vaddr_t *handler_address,
                               int *lowest_priviledge);
 
 #endif /* _SOS_IDT_H_ */