From mboxrd@z Thu Jan  1 00:00:00 1970
From: Hamish Moffatt <hamish@cloud.net.au>
Subject: Re: Slightly OT: Perl question
Date: Sun, 16 Mar 2003 09:46:04 +1100
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To: John Ackermann N8UR <jra@febo.com>
Cc: linux-hams@vger.kernel.org

On Sat, Mar 15, 2003 at 02:24:47PM -0500, John Ackermann N8UR wrote:
> I need to:
> 
> (a) test whether one bit of a byte is set or not (e..g, is bit 5 of $myvar 
> a 1 or a 0);
> 
> and
> 
> (b) do a binary AND of two bytes (in other words, apply a bitmask).

Binary AND is the "&" operator as in C. So

$c = $a & $b;
$y = $x & 0xFF;

etc achieves (b), and similarly for (a),

if ($myvar & 0x20) {
    ....
}

or perhaps more readably:

if ($myvar & (1 << 5)) {
    ....
}


Hamish
-- 
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>