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Re: Changes to make /dev/*random better sooner
On Apr 8, 2014, at 21:33, Thor Lancelot Simon <tls%panix.com@localhost> wrote:
> On Wed, Apr 09, 2014 at 02:43:23AM +0100, Mindaugas Rasiukevicius wrote:
>> Few fragments which caught my eye while skimming through the diff..
>>
>>> #if defined(__HAVE_CPU_COUNTER)
>>> - if (cpu_hascounter())
>>> - return (cpu_counter32());
>>> + if (cpu_hascounter() && sizeof(cpu_counter() == sizeof(uint64_t))) {
>>> + return (cpu_counter());
>>> + }
>>> #endif
>>
>> ??
>
> We provide no MI API for obtaining a counter value of any known size except
> 32 bits, unfortunately. The instrumentation I added while developing these
> changes revealed that the delta entropy estimator was terribly broken due
> to wraparound; changing it to 64 bits is the fix.
I don't have any knowledge or opinion about that, but maybe the "??"
has to do with the sizeof? I think the parens are wrong; they're around
the entire equality comparison.
--
Name: Dave Huang | Mammal, mammal / their names are called /
INet: khym%azeotrope.org@localhost | they raise a paw / the bat, the cat /
FurryMUCK: Dahan | dolphin and dog / koala bear and hog -- TMBG
Dahan: Hani G Y+C 38 Y++ L+++ W- C++ T++ A+ E+ S++ V++ F- Q+++ P+ B+ PA+ PL++
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