[Vm-dev] FloatMathPlugin crashes the VM if compiled with gcc optimization

Igor Stasenko siguctua at gmail.com
Sun Dec 26 23:30:51 UTC 2010


On 27 December 2010 00:17, Igor Stasenko <siguctua at gmail.com> wrote:
> On 26 December 2010 23:32, Andreas Raab <andreas.raab at gmx.de> wrote:
>>
>> On 12/26/2010 10:19 PM, Igor Stasenko wrote:
>>>
>>> low level C code which pretending to know how to do it 'right' +
>>> C compiler , who also knowing how to do it 'right' ===>>  mess in result
>>> :)
>>
>> Well, I'm sorry but the C code does bit manipulation according to IEEE 754
>> so it's hard to blame that code for overly aggressive gcc optimizations.
>> FWIW, the FloatMathPlugin must also be compiled with -mno-fused-madd as this
>> would produce another source of differences depending on whether a compiler
>> chooses to use fmadd or not.
>>
> ok. added :)
>
> Btw, i found another library:
> http://www.jhauser.us/arithmetic/SoftFloat.html
>
> looks like this one don't have problems with gcc -O2,
> because at "SoftFloat speed" it says that it is compiled with this option.
>
oh , forget it.. it  only contains basic operations like add , mul, pow etc
but not sin / cos / tan

>
>> Cheers,
>>  - Andreas
>>
>
>
>
> --
> Best regards,
> Igor Stasenko AKA sig.
>



-- 
Best regards,
Igor Stasenko AKA sig.


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