# IntVal(float) Returns Different Values

- Thread: https://externals.io/message/22527
- Original archive: https://news-web.php.net/php.internals/22527
- Started by Bruce on 2006-03-20T00:53:30+00:00
- Messages: 4
- Reply by email to internals@lists.php.net
- More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt

---

## #22527 — Bruce — 2006-03-20T00:53:30+00:00

URL: https://externals.io/message/22527#22527

I am having trouble porting some code originally written in Borland Delphi
to PHP. The Delphi code expects certain behavior on integer overflows that I
can only duplicate on some PHP systems. For example:

$BB = -2181087916;
$AA = (int)$BB;
$AA = intval($BB);

On some systems, $AA will be int(-2147483648), however, on most systems, $AA
will be int(2113879380), which is the same value truncated at 32 bits. It is
this latter behavior that I need to properly port the Delphi code.

Can someone suggest a way to do this that is consistent on all platforms?
For reference, I am attaching the Delphi code and my PHP port.

Thanks...

--Bruce

{quick (block) mixer routine}
procedure MixBlock(const Matrix : T128bit; var Block; Encrypt : Boolean);

const
  CKeyBox : array [False..True, 0..3, 0..2] of LongInt =
    (((0, 3, 1), (2, 1, 3), (1, 0, 2), (3, 2, 0)),
    ((3, 2, 0), (1, 0, 2), (2, 1, 3), (0, 3, 1)));

var
  Blocks : array [0..1] of LongInt absolute Block;
  Work : LongInt;
  Right : LongInt;
  Left : LongInt;
  R : LongInt;
  AA, BB : LongInt;
  CC, DD : LongInt;

begin
  Right := Blocks[0];
  Left := Blocks[1];

  for R := 0 to 3 do begin
  {transform the right side}
    AA := Right;
    BB := Matrix[CKeyBox[Encrypt, R, 0]];
    CC := Matrix[CKeyBox[Encrypt, R, 1]];
    DD := Matrix[CKeyBox[Encrypt, R, 2]];

    AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 7);
    BB := BB + AA; AA := AA + BB; BB := BB xor (BB shl 13);
    CC := CC + BB; BB := BB + CC; CC := CC xor (CC shr 17);
    DD := DD + CC; CC := CC + DD; DD := DD xor (DD shl 9);

    AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 3);
    BB := BB + AA; BB := BB xor (BB shl 7);
    CC := CC + BB;
    CC := CC xor (DD shr 15);
    DD := DD + CC;
    DD := DD xor (DD shl 11);

    Work := Left xor DD;
    Left := Right;
    Right := Work;
  end;

  Blocks[0] := Left;
  Blocks[1] := Right;
end;

Here is my PHP port:

 <?php
function zeroFill($a, $b)
{
  $z = hexdec(80000000);
  if ($z & $a)
  {
    $a >>= 1;
    $a &= (~ $z);
    $a |= 0x40000000;
    $a >>= ($b-1);
  }
  else
  {
    $a >>= $b;
  }
  return $a;
}

function MixBlock($AKey, &$ACode, $Encrypt)
{
  $CKeyBox = array(array(3, 2, 0), array(1, 0, 2), array(2, 1, 3), array(0,
3, 1));

  $Right = $ACode[0];
  $Left = $ACode[1];

  for ($R=0; $R<=3; $R++)
  {
    $AA = $Right;
    if ($Encrypt)
    {
      $BB = $AKey[$CKeyBox[$R][0]];
      $CC = $AKey[$CKeyBox[$R][1]];
      $DD = $AKey[$CKeyBox[$R][2]];
    }
    else
    {
      $BB = $AKey[$CKeyBox[3-$R][0]];
      $CC = $AKey[$CKeyBox[3-$R][1]];
      $DD = $AKey[$CKeyBox[3-$R][2]];
    }

    $AA = (int)$AA + (int)$DD;
    $DD = (int)$DD + (int)$AA;
    $AA = (int)$AA ^ zeroFill($AA, 7);
    $BB = (int)$BB + (int)$AA;
    $AA = (int)$AA + (int)$BB;

    $BB = (int)$BB ^ ((int)$BB << 13);
    $CC = (int)$CC + (int)$BB; $BB = (int)$BB + (int)$CC;
    $CC = (int)$CC ^ zeroFill($CC, 17);
    $DD = (int)$DD + (int)$CC; $CC = (int)$CC + (int)$DD;
    $DD = (int)$DD ^ ((int)$DD << 9);

    $AA = (int)$AA + (int)$DD; $DD = (int)$DD + (int)$AA;
    $AA = (int)$AA ^ zeroFill($AA, 3);
    $BB = (int)$BB + (int)$AA;
    $BB = (int)$BB ^ (int)((int)$BB << 7);
    $CC = (int)$CC + (int)$BB;
    $CC = (int)$CC ^ zeroFill($DD, 15);
    $DD = (int)$DD + (int)$CC;
    $DD = (int)$DD ^ (int)((int)$DD << 11);

    $Work = $Left ^ $DD;
    $Left = $Right;
    $Right = $Work;
  }

  $ACode[0] = $Left;
  $ACode[1] = $Right;
}
?

---

## #22529 — Jasper Bryant-Greene — 2006-03-20T08:22:21+00:00

URL: https://externals.io/message/22527#22529 · In reply to: #22527

You want the php-general mailing list. This list is for discussing 
development of the PHP language and runtime...

Jasper

Bruce wrote:
> I am having trouble porting some code originally written in Borland Delphi
> to PHP. The Delphi code expects certain behavior on integer overflows that I
> can only duplicate on some PHP systems. For example:
> 
> $BB = -2181087916;
> $AA = (int)$BB;
> $AA = intval($BB);
> 
> On some systems, $AA will be int(-2147483648), however, on most systems, $AA
> will be int(2113879380), which is the same value truncated at 32 bits. It is
> this latter behavior that I need to properly port the Delphi code.
> 
> Can someone suggest a way to do this that is consistent on all platforms?
> For reference, I am attaching the Delphi code and my PHP port.
> 
> Thanks...
> 
> --Bruce
> 
> {quick (block) mixer routine}
> procedure MixBlock(const Matrix : T128bit; var Block; Encrypt : Boolean);
> 
> const
>   CKeyBox : array [False..True, 0..3, 0..2] of LongInt =
>     (((0, 3, 1), (2, 1, 3), (1, 0, 2), (3, 2, 0)),
>     ((3, 2, 0), (1, 0, 2), (2, 1, 3), (0, 3, 1)));
> 
> var
>   Blocks : array [0..1] of LongInt absolute Block;
>   Work : LongInt;
>   Right : LongInt;
>   Left : LongInt;
>   R : LongInt;
>   AA, BB : LongInt;
>   CC, DD : LongInt;
> 
> begin
>   Right := Blocks[0];
>   Left := Blocks[1];
> 
>   for R := 0 to 3 do begin
>   {transform the right side}
>     AA := Right;
>     BB := Matrix[CKeyBox[Encrypt, R, 0]];
>     CC := Matrix[CKeyBox[Encrypt, R, 1]];
>     DD := Matrix[CKeyBox[Encrypt, R, 2]];
> 
>     AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 7);
>     BB := BB + AA; AA := AA + BB; BB := BB xor (BB shl 13);
>     CC := CC + BB; BB := BB + CC; CC := CC xor (CC shr 17);
>     DD := DD + CC; CC := CC + DD; DD := DD xor (DD shl 9);
> 
>     AA := AA + DD; DD := DD + AA; AA := AA xor (AA shr 3);
>     BB := BB + AA; BB := BB xor (BB shl 7);
>     CC := CC + BB;
>     CC := CC xor (DD shr 15);
>     DD := DD + CC;
>     DD := DD xor (DD shl 11);
> 
>     Work := Left xor DD;
>     Left := Right;
>     Right := Work;
>   end;
> 
>   Blocks[0] := Left;
>   Blocks[1] := Right;
> end;
> 
> Here is my PHP port:
> 
>  <?php
> function zeroFill($a, $b)
> {
>   $z = hexdec(80000000);
>   if ($z & $a)
>   {
>     $a >>= 1;
>     $a &= (~ $z);
>     $a |= 0x40000000;
>     $a >>= ($b-1);
>   }
>   else
>   {
>     $a >>= $b;
>   }
>   return $a;
> }
> 
> function MixBlock($AKey, &$ACode, $Encrypt)
> {
>   $CKeyBox = array(array(3, 2, 0), array(1, 0, 2), array(2, 1, 3), array(0,
> 3, 1));
> 
>   $Right = $ACode[0];
>   $Left = $ACode[1];
> 
>   for ($R=0; $R<=3; $R++)
>   {
>     $AA = $Right;
>     if ($Encrypt)
>     {
>       $BB = $AKey[$CKeyBox[$R][0]];
>       $CC = $AKey[$CKeyBox[$R][1]];
>       $DD = $AKey[$CKeyBox[$R][2]];
>     }
>     else
>     {
>       $BB = $AKey[$CKeyBox[3-$R][0]];
>       $CC = $AKey[$CKeyBox[3-$R][1]];
>       $DD = $AKey[$CKeyBox[3-$R][2]];
>     }
> 
>     $AA = (int)$AA + (int)$DD;
>     $DD = (int)$DD + (int)$AA;
>     $AA = (int)$AA ^ zeroFill($AA, 7);
>     $BB = (int)$BB + (int)$AA;
>     $AA = (int)$AA + (int)$BB;
> 
>     $BB = (int)$BB ^ ((int)$BB << 13);
>     $CC = (int)$CC + (int)$BB; $BB = (int)$BB + (int)$CC;
>     $CC = (int)$CC ^ zeroFill($CC, 17);
>     $DD = (int)$DD + (int)$CC; $CC = (int)$CC + (int)$DD;
>     $DD = (int)$DD ^ ((int)$DD << 9);
> 
>     $AA = (int)$AA + (int)$DD; $DD = (int)$DD + (int)$AA;
>     $AA = (int)$AA ^ zeroFill($AA, 3);
>     $BB = (int)$BB + (int)$AA;
>     $BB = (int)$BB ^ (int)((int)$BB << 7);
>     $CC = (int)$CC + (int)$BB;
>     $CC = (int)$CC ^ zeroFill($DD, 15);
>     $DD = (int)$DD + (int)$CC;
>     $DD = (int)$DD ^ (int)((int)$DD << 11);
> 
>     $Work = $Left ^ $DD;
>     $Left = $Right;
>     $Right = $Work;
>   }
> 
>   $ACode[0] = $Left;
>   $ACode[1] = $Right;
> }
> ?

---

## #22530 — Ron Korving — 2006-03-20T08:35:38+00:00

URL: https://externals.io/message/22527#22530 · In reply to: #22529

Nonetheless, it's interesting why (int)$int and intval($int) will give 
different results...

Ron

"Jasper Bryant-Greene" <jasper@album.co.nz> schreef in bericht 
news:441E663D.3050003@album.co.nz...
> You want the php-general mailing list. This list is for discussing 
> development of the PHP language and runtime...
>
> Jasper
>
> Bruce wrote:
> > […]

---

## #22538 — Bruce — 2006-03-20T15:08:17+00:00

URL: https://externals.io/message/22527#22538 · In reply to: #22529

I understand what you are saying, however, I did ask there, and no one could
help me, and one person suggested I ask on the developer's list.

It would be great to at least understand what is going on.

--Bruce


>
> You want the php-general mailing list. This list is for discussing
> development of the PHP language and runtime...
>
> Jasper