Unsigned variables

[bgolab]

Hi All,

I have a code fragment in C and I want to convert it to AutoIt:

table is unsigned char

================

unsigned int x, y, z;

y = key;

x=0

for (i = 0; i<3; i++) {

x = (x & 0xffffff00) | table;

y ^= x;

y += x;

x <<= 8;

y ^= x;

x <<= 8;

y -= x;

x <<= 8;

y ^= x;

z = y & 0x1f;

y = (y << z) | (y >> (32 - z));

}

return y;

It works fine in C but there is a problem in AutoIt. During bit operation (i.e. BitXOR which represents ^) some variables like y (declared in C as unsigned) are treated as signed in AutoIt.

How to fix it in AutoIt?

Bogdan

[PsaltyDS]

Hi All,

I have a code fragment in C and I want to convert it to AutoIt:

It works fine in C but there is a problem in AutoIt. During bit operation (i.e. BitXOR which represents ^) some variables like y (declared in C as unsigned) are treated as signed in AutoIt.

How to fix it in AutoIt?

Bogdan

You didn't show your AutoIt code, so there's no telling what you did wrong. BitXOR works fine:

$y = 0x0FF
$x = 0xFFFFFF00
$z = BitXOR($x, $y)
$sAns = "0x" & Hex($z, 8)
MsgBox(64, "Answer", $sAns)

Can you post some AuotIt code that gives an unexpected answer?

[bgolab]

You didn't show your AutoIt code, so there's no telling what you did wrong. BitXOR works fine:

$y = 0x0FF
$x = 0xFFFFFF00
$z = BitXOR($x, $y)
$sAns = "0x" & Hex($z, 8)
MsgBox(64, "Answer", $sAns)

Can you post some AuotIt code that gives an unexpected answer?

The code in AutoIT

$y=$key

$x=0

For $i=0 To 2 Step 1

$xx=BitAND($x,0xffffff00)

$x=BitOR($xx, Asc($znak[$i]))

$y=BitXOR($y, $x)

$y=$y+$x

$x=BitShift($x,-8)

$y=BitXOR($y, $x)

$x=BitShift($x,-8)

$y=$y-$x

$x=BitShift($x,-8)

$y=BitXOR($y, $x)

$z=BitAND($y,0x1F)

$y1=BitShift($y,-$z)

$y2=BitShift($y,32-$z)

$y=BitOR($y1, $y2)

Next

Return $y

[SkinnyWhiteGuy]

I've had the same problem before, answer for me was right before returning, convert your number $y to hex using the builtin Hex() function, then use the following function to convert that into an unsigned number:

Func Hex2Dec($hex)
    Local $dec = 0, $i
    For $i = 0 To StringLen($hex) - 1
        $dec += Dec(StringMid($hex, StringLen($hex)-$i,1)) * (16 ^ $i)
    Next
    Return $dec
EndFunc

[PsaltyDS]

I've had the same problem before, answer for me was right before returning, convert your number $y to hex using the builtin Hex() function, then use the following function to convert that into an unsigned number:

Hmm... Is this what you expected from that?

$x = 0xFFFFFF00
ConsoleWrite("Debug: $x = " & $x & @LF) ; = -256
$y = Hex2Dec($x)
ConsoleWrite("Debug: $y = " & $y & @LF) ; = 598

Func Hex2Dec($hex)
    Local $dec = 0, $i
    For $i = 0 To StringLen($hex) - 1
        $dec += Dec(StringMid($hex, StringLen($hex)-$i,1)) * (16 ^ $i)
    Next
    Return $dec
EndFunc

Edit: Oops, I see it now. Have to pass string representation by changing the first line to: $x = Hex(0xFFFFFF00, 8)

Then I get $x = $x = FFFFFF00; $y = 4294967040.

Edited November 16, 2007 by PsaltyDS

[bgolab]

Hmm... Is this what you expected from that?

$x = 0xFFFFFF00
ConsoleWrite("Debug: $x = " & $x & @LF) ; = -256
$y = Hex2Dec($x)
ConsoleWrite("Debug: $y = " & $y & @LF) ; = 598

Func Hex2Dec($hex)
    Local $dec = 0, $i
    For $i = 0 To StringLen($hex) - 1
        $dec += Dec(StringMid($hex, StringLen($hex)-$i,1)) * (16 ^ $i)
    Next
    Return $dec
EndFunc

Edit: Oops, I see it now. Have to pass string representation by changing the first line to: $x = Hex(0xFFFFFF00, 8)

Then I get $x = $x = FFFFFF00; $y = 4294967040.

---

I'll try it. I suspect a problem with "y -= x;" because signed operation /AutoIt/ involves a correction (probably nased on CPU's "overflow" bit).

Maybe it is a good idea to simulate CPU operation using Autoit in this case. I mean generic summer and substractor:) Just joking...

Anyway, unsigned variables seem to useful even in AutoIt...

Bogdan