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Request #6368 Bitwise NOT does not work
Submitted: 2000-08-26 12:56 UTC Modified: 2002-01-28 20:13 UTC
From: jonny at 1409 dot org Assigned:
Status: Closed Package: Feature/Change Request
PHP Version: 4.0.1pl2 OS: Linux 2.2.16
Private report: No CVE-ID: None
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From: jonny at 1409 dot org
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 [2000-08-26 12:56 UTC] jonny at 1409 dot org 
Maybe i'm just too stupid, but this one is strange:

The logical operator ~ (bitwise NOT) does not behave as expected. When
doing a "~1" (00000000000000000000000000000001), i get
2 (10000000000000000000000000000001) so it only seems to
invert the first bit?!

Furthermore when doing some simple mathematicaloperations, PHP behaves extremely annoing. Right-shifting (>>) a negative number will
always produce a negative result, i.e. the +/- bit gets not
shifted. Although you are right when you claim that this one is ok,
there are situations when you want the sign bit to get also shifted,
and there seems to be no simple way for doing that in PHP :-(

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 [2000-08-26 12:58 UTC] jonny at 1409 dot org 
Sorry, there's an error in my Bug report.

When I do a "~1" i get -2, not 2.

Sorry again...
 [2000-08-26 13:40 UTC] stas@php.net 
Why did you decide that -2 is 10000000000000000000000000000001? It isn't.
 [2000-08-26 13:41 UTC] stas@php.net 
And signed shift operations is not a bug, moving to feature request.
 [2002-01-28 20:13 UTC] yohgaki@php.net 
Is this feasible? 
I think it's not, unless we support unsinged int/long type......
And it will be more confusing than bitwise operation....

Won't change.

Please feel free to reopen if you are willing to discuss more about this.
 
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