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/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
 *
 *   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, Inc., 53 Temple Place Ste 330,
 *   Boston MA 02111-1307, USA; either version 2 of the License, or
 *   (at your option) any later version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

#ifndef SYSLXINT_H
#define SYSLXINT_H

#include "syslinux.h"

/*
 * Access functions for littleendian numbers, possibly misaligned.
 */
static inline uint8_t get_8(const uint8_t *p)
{
  return *(const uint8_t *)p;
}

static inline uint16_t get_16(const uint16_t *p)
{
#if defined(__i386__) || defined(__x86_64__)
  /* Littleendian and unaligned-capable */
  return *(const uint16_t *)p;
#else
  return (uint16_t)p[0] + ((uint16_t)p[1] << 8);
#endif
}

static inline uint32_t get_32(const uint32_t *p)
{
#if defined(__i386__) || defined(__x86_64__)
  /* Littleendian and unaligned-capable */
  return *(const uint32_t *)p;
#else
  return (uint32_t)p[0] + ((uint32_t)p[1] << 8) +
    ((uint32_t)p[2] << 16) + ((uint32_t)p[3] << 24);
#endif
}

static inline void set_16(uint16_t *p, uint16_t v)
{
#if defined(__i386__) || defined(__x86_64__)
  /* Littleendian and unaligned-capable */
  *(uint16_t *)p = v;
#else
  p[0] = (v & 0xff);
  p[1] = ((v >> 8) & 0xff);
#endif
}

static inline void set_32(uint32_t *p, uint32_t v)
{
#if defined(__i386__) || defined(__x86_64__)
  /* Littleendian and unaligned-capable */
  *(uint32_t *)p = v;
#else
  p[0] = (v & 0xff);
  p[1] = ((v >> 8) & 0xff);
  p[2] = ((v >> 16) & 0xff);
  p[3] = ((v >> 24) & 0xff);
#endif
}

#define SECTOR_SHIFT	9	/* 512-byte sectors */
#define SECTOR_SIZE	(1 << SECTOR_SHIFT)

#define LDLINUX_MAGIC	0x3eb202fe

/* Patch area for disk-based installers */
struct patch_area {
  uint32_t magic;		/* LDLINUX_MAGIC */
  uint32_t instance;		/* Per-version value */
  uint16_t data_sectors;
  uint16_t adv_sectors;
  uint32_t dwords;
  uint32_t checksum;
  uint32_t currentdir;
  uint16_t secptroffset;
  uint16_t secptrcnt;
};

  /* FAT bootsector format, also used by other disk-based derivatives */
struct boot_sector {
  uint8_t	bsJump[3];
  char		bsOemName[8];
  uint16_t	bsBytesPerSec;
  uint8_t	bsSecPerClust;
  uint16_t	bsResSectors;
  uint8_t	bsFATs;
  uint16_t	bsRootDirEnts;
  uint16_t	bsSectors;
  uint8_t	bsMedia;
  uint16_t	bsFATsecs;
  uint16_t	bsSecPerTrack;
  uint16_t	bsHeads;
  uint32_t	bsHiddenSecs;
  uint32_t	bsHugeSectors;

  union {
    struct {
      uint8_t	DriveNumber;
      uint8_t	Reserved1;
      uint8_t	BootSignature;
      uint32_t	VolumeID;
      char	VolumeLabel[11];
      char	FileSysType[8];
      uint8_t	Code[442];
    }  __attribute__((packed)) bs16;
    struct {
      uint32_t	FATSz32;
      uint16_t	ExtFlags;
      uint16_t	FSVer;
      uint32_t	RootClus;
      uint16_t	FSInfo;
      uint16_t	BkBootSec;
      uint8_t	DriveNumber;
      uint8_t	Reserved1;
      uint8_t	BootSignature;
      uint32_t	VolumeID;
      char	VolumeLabel[11];
      char	FileSysType[8];
      uint8_t	Code[414];
    } __attribute__((packed)) bs32;
  } __attribute__((packed));

  uint32_t	NextSector;	/* Pointer to the first unused sector */
  uint16_t	MaxTransfer;	/* Max sectors per transfer */
  uint16_t	bsSignature;
} __attribute__((packed));

#define bsHead      bsJump
#define bsHeadLen   offsetof(struct boot_sector, bsOemName)
#define bsCode	    bs32.Code	/* The common safe choice */
#define bsCodeLen   (offsetof(struct boot_sector, bsSignature) - \
		     offsetof(struct boot_sector, bsCode))

#endif /* SYSLXINT_H */