Re: Help with some clever bit operations
| From: | Barry | Date: | Tue, 13 Jun 2006 09:39:26 +0000 |
| Subject: | Re: Help with some clever bit operations | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-237870@lists.php.net to get a copy of this message | ||
Niels schrieb:
Hi, I have a problem I can solve with some loops and if-thens, but I'm sure it can be done with bit operations -- that would be prettier. I've tried to work it out on paper, but I keep missing the final solution. Maybe I'm missing something obvious... The problem: A function tries to update an existing value, but is only allowed to write certain bits. There are 3 variables: A: the existing value, eg. 10110101 B: what the function wants to write, eg. 01011100 C: which bits the function is allowed to write, eg. 00001111 With these examples, 10111100 should be written. How do I combine A, B and C to get that result? addition probably?Btw. the result of the addition would be : 111010101 Barry -- Smileys rule (cX.x)C --o(^_^o) Dance for me! ^(^_^)o (o^_^)o o(^_^)^ o(^_^o)