/******************************************************************************
** Functions by Derrick Sobodash
** http://www.cinnamonpirate.com/
** Submitted to ROM Hacking.net on July 3, 2006
******************************************************************************/

/******************************************************************************
** hi2lorom()
*******************************************************************************
** syntax: int hi2lorom(int value)
*******************************************************************************
** Converts a hirom SNES offset to a lorom value and returns the result as
** an integer.
*******************************************************************************
** Example: echo "HiROM:0x12f90 -- LoROM:0x" . dechex(hi2lorom(0x12f90));
** Return : HiROM:0x12f90 -- LoROM:0x2af90
******************************************************************************/

function hi2lorom($value)
{

  if($value > 0xffffff)
    die("Error: hi2lorom(): Cannot accept values greater than 24-bits\n\n");

  $value = ((int) ($value / 0x10000)) * 2 * 0x10000 + ($value % 0x10000);

  if(($value % 0x10000) > 0x8000)
    $value += 0x10000;
  else
    $value += 0x8000;

  return(((int) ($value / 0x10000) * 0x10000) + ($value % 0x10000));
}


/******************************************************************************
** lo2hirom()
*******************************************************************************
** syntax: int lo2hirom(int value)
*******************************************************************************
** Converts a lorom SNES offset to a hirom value and returns the result as
** an integer.
*******************************************************************************
** Example: echo "HiROM:0x" . dechex(lo2hirom(0xb9f90)) . " -- LoROM:0xb9f90";
** Return : HiROM:0x59f90 -- LoROM:0xb9f90
******************************************************************************/

function lo2hirom($value)
{

  if($value > 0xffffff)
    die("Error: lo2hirom(): Cannot accept values greater than 24-bits\n\n");

  // We need to cast this calue to int type, otherwise we will get
  // a floating point number
  if((int) ($value / 0x10000) % 2 != 0)
    $value -= 0x10000;
  else
    $value -= 0x8000;

  return((int) ($value / 0x10000) * 0x8000 + ($value % 0x10000));

}