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rbhkamal

unsigned bit shift

6 posts in this topic

#1 ·  Posted (edited)

I'm trying to turn on the MSB in an autoit int using the following logic:

11111 (Starting with a -1)

01111 (Shift right one)

10000 (not)

The problem (my problem) is that autoit does a logic shift for the number as a signed number and thus I endup with -1 again. Is there a way to tell the shift that the number is unsigned?

Here is my test code

Local $L_iRc = 0
$L_iRc = BitNOT($L_iRc)
 ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @crlf & '>Error code: ' & @error & @crlf) ;### Debug Console 
$L_iRc = BitShift( $L_iRc , 1 )
    ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @crlf & '>Error code: ' & @error & @crlf) ;### Debug Console
$L_iRc = BitNOT($L_iRc)
    ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @crlf & '>Error code: ' & @error & @crlf) ;### Debug Console

Also is there a way to get the size of a number in autoit?

Thanks!

Edited by rbhkamal

"When the power of love overcomes the love of power, the world will know peace"-Jimi Hendrix

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#2 ·  Posted (edited)

AutoIt int type is signed. Get over it. Unsigned "uint" for AutoIt only exists in DLL structs.

I don't see why you want derive this through shifting, but you could do this:

Local $L_iRc = 0x40000000
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @CRLF & '>Error code: ' & @error & @CRLF & @CRLF) ;### Debug Console
$L_iRc = BitShift($L_iRc, -1)
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @CRLF & '>Error code: ' & @error & @CRLF & @CRLF) ;### Debug Console

...or this:

Local $L_iRc = 1
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @CRLF & '>Error code: ' & @error & @CRLF & @CRLF) ;### Debug Console
$L_iRc = BitRotate($L_iRc, -1, "D")
ConsoleWrite('@@ Debug(' & @ScriptLineNumber & ') : $L_iRc = ' & $L_iRc & @CRLF & '>Error code: ' & @error & @CRLF & @CRLF) ;### Debug Console

The result either way is 0x80000000 binary (MSB set), which is -2147483648 as a signed int.

:idea:

P.S. What does "size of a number" mean? Maybe Abs()?

Edited by PsaltyDS

Valuater's AutoIt 1-2-3, Class... Is now in Session!For those who want somebody to write the script for them: RentACoder"Any technology distinguishable from magic is insufficiently advanced." -- Geek's corollary to Clarke's law

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LOL.... or this:

$z = BitShift( 1, -31)

That was from the help file...

I just wanted to know how many bytes my number was occupying so I'll be able to know which bit to turn on. The help file had the answer... 32 bit!

Thanks for the help man, I'll be using BitRotate($L_iRc, -1, "D")


"When the power of love overcomes the love of power, the world will know peace"-Jimi Hendrix

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AFAICT the current state of affairs is that AutoIt integers are 64-bit signed ints but hexadecimal and bit operations (the 0x..., Hex, Bit* functions) only operate on 32-bit ints.

That makes the answer to your last question less than precise. You can still perform calculations on 64-bit ints:

ConsoleWrite(0x12345678 * 1024 * 1024 * 1024 & @LF) ; clearly more than 32-bit integer


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The type dynamically changes:

$iVal = 0x12345678
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)
$iVal *= 1024 * 1024 * 1024
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)

:idea:


Valuater's AutoIt 1-2-3, Class... Is now in Session!For those who want somebody to write the script for them: RentACoder"Any technology distinguishable from magic is insufficiently advanced." -- Geek's corollary to Clarke's law

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Unfortunately, it won't automatically switch to floating point:

$iVal = 0x12345678
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)
$iVal *= 1024 * 1024 * 1024
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)
$iVal *= 1024 * 1024 * 1024
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF) ; <== $iVal = -9223372036854775808; Type = Int64

Forcing float prevents that:

$iVal = 0x12345678
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)
$iVal *= 1024 * 1024 * 1024
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF)

$iVal *= 1.00 * 1024 * 1024 * 1024
ConsoleWrite("$iVal = " & $iVal & "; Type = " & VarGetType($iVal) & @LF) ; <==  $iVal = 3.52125166033187e+026; Type = Double

:idea:


Valuater's AutoIt 1-2-3, Class... Is now in Session!For those who want somebody to write the script for them: RentACoder"Any technology distinguishable from magic is insufficiently advanced." -- Geek's corollary to Clarke's law

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