pic.h

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// See the end of this file for license information.

#ifndef TORSION_PIC_H
#define TORSION_PIC_H

#include "asm.h"

class PIC;
extern PIC pic;

typedef enum {
  PIC_IO_BASE_0 = 0x20,
  PIC_IO_BASE_1 = 0xA0
} PIC_io_base;

typedef enum {
  PIC_REGISTER_DATA             = 0,
  PIC_REGISTER_COMMAND          = 0,
  PIC_REGISTER_INITIALIZE       = 1,
  PIC_REGISTER_INTERRUPT_ENABLE = 1
} PIC_register;

typedef enum {
  PIC_COMMAND_READ_INTERRUPT_REQUESTS            = 0x0A,
  PIC_COMMAND_READ_INTERRUPTS_IN_SERVICE         = 0x0B,
        
  PIC_COMMAND_END_OF_INTERRUPT                   = 0x20,
  PIC_COMMAND_ROTATIN_PRIORITY_END_OF_INTERRUPT  = 0xA0,

  PIC_COMMAND_CLEAR_SPECIAL_MASK_MODE            = 0x48,
  PIC_COMMAND_SET_SPECIAL_MASK_MODE              = 0x68,
        
  PIC_COMMAND_END_OF_INTERRUPT_0                 = 0x60,
  PIC_COMMAND_END_OF_INTERRUPT_1                 = 0x61,
  PIC_COMMAND_END_OF_INTERRUPT_2                 = 0x62,
  PIC_COMMAND_END_OF_INTERRUPT_3                 = 0x63,
  PIC_COMMAND_END_OF_INTERRUPT_4                 = 0x64,
  PIC_COMMAND_END_OF_INTERRUPT_5                 = 0x65,
  PIC_COMMAND_END_OF_INTERRUPT_6                 = 0x66,
  PIC_COMMAND_END_OF_INTERRUPT_7                 = 0x67,
        
  PIC_COMMAND_SELECT_IRQ_PRIORITY_0              = 0xC0,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_1              = 0xC1,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_2              = 0xC2,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_3              = 0xC3,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_4              = 0xC4,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_5              = 0xC5,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_6              = 0xC6,
  PIC_COMMAND_SELECT_IRQ_PRIORITY_7              = 0xC7,

  PIC_COMMAND_INITIALIZATION_MODE                = 0x11
} PIC_command;


class PIC {
protected:
  unsigned char masks[2];   

  inline unsigned char
  read_register(PIC_io_base io_base, PIC_register register_num) {
    return inb(io_base + register_num);
  }

  inline void
  write_register(PIC_io_base io_base, PIC_register register_num,
     unsigned char data) { 
    outb(data, io_base + register_num);
  }

public:
  void
  init();

  inline void
  signal_end_of_irq(unsigned char int_num) {
    if (int_num >= 0x20) {
      unsigned char irq_num = int_to_irq(int_num);
      write_register((irq_num < 8) ? PIC_IO_BASE_0 : PIC_IO_BASE_1,
                     PIC_REGISTER_COMMAND, PIC_COMMAND_END_OF_INTERRUPT);
    }
  }

  void
  mask_irq(unsigned char int_num);

  void
  unmask_irq(unsigned char int_num);

  static inline unsigned char
  int_to_irq(unsigned char irq_num) {
    return irq_num - 0x20;
  }

  void
  print();
};

#endif

/* Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman
 *
 * 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 (in the COPYING file).
 * 
 * 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
 */

---

Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman