/* 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/>. */

#ifndef _SYSTEM_DATA_STRUCTS_H
#define _SYSTEM_DATA_STRUCTS_H

/* descripteurs */

/* types de descripteurs systeme */
#define SDT_AVL286TSS   0x1     /* Available 286 TSS */
#define SDT_LDT         0x2     /* LDT */
#define SDT_BSY286TSS   0x3     /* Busy 286 TSS */
#define SDT_CALLGT      0x4     /* Call Gate */
#define SDT_TASKGT      0x5     /* Task Gate */
#define SDT_286INTGT    0x6     /* 286 Interrupt Gate */
#define SDT_286TRAPGT   0x7     /* 286 Trap Gate */
#define SDT_AVL386TSS   0x9     /* Available 386 TSS */
#define SDT_BSY386TSS   0xb     /* Busy 386 TSS */
#define SDT_386CALLGT   0xc     /* 386 Call Gate */
#define SDT_386INTGT    0xe     /* 386 Interrupt Gate */
#define SDT_386TRAPGT   0xf     /* 386 Trap Gate */

struct descr_data_struct {
  unsigned type : 1; /* 0=system, 1=segment */
  union {
    struct { /* system */
      unsigned system_type : 4;
    };
    struct { /* segment */
      unsigned accessed : 1;
      unsigned segment_type : 1; /* 0=data, 1=code */
      union {
        struct { /* data */
          unsigned writable : 1;
          unsigned expand_down : 1;
        };
        struct { /* code */
          unsigned readable : 1;
          unsigned conforming : 1;
        };
      };
    };
  };
  unsigned dpl : 2;
  unsigned present : 1;
  union {
    struct { /* present */
      union {
        struct { /* segment, ldt, tss */
          unsigned long base;
          unsigned limit : 20;
          unsigned granularity : 1;
          unsigned avl : 1;
          union {
            unsigned x : 1; /* system */
            unsigned big : 1; /* data */
            unsigned def : 1; /* code */
          };
        };
        struct { /* gate */
          unsigned short selector;
          union {
            struct { /* call gate, interrupt gate, trap gate */
              unsigned long offset;
              union {
                unsigned dword_count : 5; /* call gate */
              };
            };
          };
        };
      };
    };
  };
};

/* selecteurs */

struct sel_data_struct {
  unsigned rpl : 2;
  unsigned table_ind : 1;
  unsigned index : 13;
};

/* adresses lineaires */

struct linear_address_data_struct {
  unsigned dir : 10;
  unsigned page : 10;
  unsigned offset : 12;
};

/* entrees de table des pages */

struct page_table_entry_data_struct {
  unsigned present : 1;
  union {
    struct { /* present */
      unsigned rw : 1; /* 0=read-only, 1=read/write */
      unsigned us : 1; /* 0=supervisor, 1=user */
      unsigned accessed : 1;
      unsigned dirty : 1;
      unsigned avail : 3;
      unsigned long page_frame_addr;
    };
  };
};

/* segments d'etat de tache */

struct tss_data_struct {
  /* champs statiques */
  unsigned long pdbr;
  unsigned short ldt;
  unsigned short ss0;
  unsigned long esp0;
  unsigned short ss1;
  unsigned long esp1;
  unsigned short ss2;
  unsigned long esp2;
  unsigned trap : 1;
  unsigned short iomap_base;

  /* champs dynamiques */
  unsigned long eax;
  unsigned long ebx;
  unsigned long ecx;
  unsigned long edx;
  unsigned long ebp;
  unsigned long esp;
  unsigned long esi;
  unsigned long edi;
  unsigned short cs;
  unsigned short ds;
  unsigned short es;
  unsigned short fs;
  unsigned short gs;
  unsigned short ss;
  unsigned long eflags;
  unsigned long eip;
  unsigned short previous;
};

/* code d'erreur */

struct error_code_data_struct {
  unsigned ext : 1;
  unsigned idt : 1;
  unsigned table_ind : 1;
  unsigned index : 13;
};

/* code d'erreur des defauts de page */

struct page_fault_error_code_data_struct {
  unsigned cause : 1; /* 0=not-present page, 1=protection violation */
  unsigned access : 1; /* 0=read, 1=write */
  unsigned mode : 1; /* 0=supervisor, 1=user */
};

#endif