Re: Help with some clever bit operations
| From: | Niels | Date: | Tue, 13 Jun 2006 11:14:19 +0000 |
| Subject: | Re: Help with some clever bit operations | ||
| References: | 1 2 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-237879@lists.php.net to get a copy of this message | ||
On Tuesday 13 June 2006 12:18, David Tulloh wrote:
> The example starting values
> $existing = 181; # = 10110101
> $new = 92; # = 01011100
> $mask = 15; # = 00001111
>
> Get the bits that will be changed
> $changing = $new & $mask; # = 12 = 00001100
>
> Get the bits that won't be changed
> $staying = $existing & ~$mask; # = 176 = 10110000
>
> Combine them together
> $result = $changing ^ $staying; # = 188 = 10111100
>
>
> David
[snip]
Thank you very much, I appreciate it!
Niels