View of xos/drivers/pic.c

/* Pilote pour le controleur d'interruptions Intel 8259A */
/* Copyright (C) 2008  Emmanuel Varoquaux
 
   This file is part of XOS.
 
   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 3 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, see <http://www.gnu.org/licenses/>. */
 
#include <asm.h>
 
void pic_init()
{
  /* sequence d'initialisation */
  outbp(0x11, 0x20); /* 8259A-1 */
  outbp(0x11, 0xa0); /* 8259A-2 */
 
  outbp(0x20, 0x21); /* adresse de base des it du 8259A-1 (0x20) */
  outbp(0x28, 0xa1); /* adresse de base des it du 8259A-2 (0x28) */
 
  outbp(0x04, 0x21); /* 8259-1 est maitre */
  outbp(0x02, 0xa1); /* 8259-2 est esclave */
 
  /* 8086 mode */
  outbp(0x01, 0x21);
  outbp(0x01, 0xa1);
 
  /* masquage des interruptions */
  outbp(0xff, 0x21);
  outbp(0xff, 0xa1);
}
 
void pic_enable_irq(unsigned int irq)
{
  if (irq < 8)
    outb(inbp(0x21) & ~(1 << irq), 0x21);
  else
    outb(inbp(0xa1) & ~(1 << (irq - 8)), 0xa1);
}
 
void pic_ack_master()
{
  outb(0x20, 0x20); /* End Of Interrupt */
}
 
void pic_ack_slave()
{
  outb(0x20, 0xa0); /* End Of Interrupt */
}