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Re: Need help identifying left most zero bit [message #30131 is a reply to message #30130]

Sat, 06 April 2002 12:43

Pavel Romashkin
Messages: 166
Registered: April 1999

Senior Member

Phil,
Download the last function from David's page here:
http://www.dfanning.com/misc_tips/binary_hex.html
Then try:

print, (where(binary(-15s) eq 0))[0]

Cheers,
Pavel

"Phil" <plmcelwee@yahoo.com> wrote in message
news:a3589d11.0204051007.10df5da6@posting.google.com...
> I'm working with negative (two's complement) 16-bit numbers and could
> use some help. What I'd like to do is have a function that will tell
> me the location of the left-most zero bit for any given negative
> 16-bit number. Here are some examples to illustrate my goal.
>
> if x = -2, which is 1111 1111 1111 1110, then return 1
> if x = -5, which is 1111 1111 1111 1011, then return 3
> if x = -15, which is 1111 1111 1111 0111, then return 4
> if x = -8, which is 1111 1111 1111 1000, then return 3
>
> Is there something built-in to IDL that will accomplish this? Or does
> anyone have any other suggestions?

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[Message index]

		Re: Need help identifying left most zero bit By: David Fanning on Sat, 06 April 2002 22:01
		Re: Need help identifying left most zero bit By: Pavel Romashkin on Sat, 06 April 2002 20:39
		Re: Need help identifying left most zero bit By: David Fanning on Sat, 06 April 2002 15:02
		Re: Need help identifying left most zero bit By: Pavel Romashkin on Sat, 06 April 2002 12:43
		Re: Need help identifying left most zero bit By: TFE on Fri, 05 April 2002 11:40
		Re: Need help identifying left most zero bit By: plmcelwee on Tue, 09 April 2002 16:53

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