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Challenge: Algorithms having only one line of code.
#94
Heres a couple i came across recently that i found quite interesting. They are for testing if an addition or subtraction causes an overflow (ie the result is out of signed range)

These examples assume that a and b are 16-bit signed values. This can be changed by changing the AND &H8000 to other values (ie &H80 for 8-bit).

Here is a link to a topic where redcrab explained to me exactly how they work

http://www.freebasic.net/forum/viewtopic.php?t=3914

Addition
Code:
overflow = ((a XOR (NOT b)) AND (a XOR (a + b)) AND &H8000) <> 0

Subtraction
Code:
overflow = ((a XOR b) AND (a XOR (a - b)) AND &H8000) <> 0
EVEN MEN OF STEEL RUST.
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Messages In This Thread
To Oracle: 2nd look at your code. - by Moneo - 06-24-2003, 09:07 PM
To Seph and Agamemnus: - by Moneo - 06-24-2003, 09:17 PM
factorial. - by Agamemnus - 06-24-2003, 09:51 PM
To Agamemnus - by Moneo - 06-24-2003, 10:21 PM
To na_th_an: - by Moneo - 06-27-2003, 03:15 AM
ok, - by Agamemnus - 06-27-2003, 05:17 PM
To Oracle re Statlib - by Moneo - 06-27-2003, 10:39 PM
Re: To na_th_an: - by na_th_an - 06-28-2003, 01:14 AM
To LooseCaboose: - by Moneo - 06-28-2003, 03:08 AM
Re: To Oracle re Statlib - by oracle - 06-28-2003, 05:50 AM
To Oracle: - by Moneo - 06-29-2003, 03:10 AM
To Ak00ma: - by Moneo - 06-30-2003, 03:39 AM
Power of 2 - by Moneo - 07-02-2003, 02:42 AM
To Antoni: - by Moneo - 07-02-2003, 03:03 AM
197 - by whitetiger0990 - 07-02-2003, 06:29 PM
To na_th_an re "replacement" logic: - by Moneo - 07-02-2003, 08:29 PM
Re ROUNDING using .5: - by Moneo - 07-02-2003, 08:47 PM
Re: Re ROUNDING using .5: - by Moneo - 03-20-2006, 06:19 AM
Challenge: Algorithms having only one line of code. - by Anonymous - 03-29-2006, 10:09 PM
Challenge: Algorithms having only one line of code. - by Anonymous - 03-29-2006, 10:24 PM
Challenge: Algorithms having only one line of code. - by Anonymous - 03-29-2006, 10:52 PM
my one-liner - by neuro - 03-30-2006, 12:08 AM
Challenge: Algorithms having only one line of code. - by yetifoot - 04-26-2006, 08:04 PM

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