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Subject: Re: Question to 64 bit experts

Author: Bo Persson

Date: 10:09:41 01/19/05

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On January 19, 2005 at 12:02:40, Andrew Williams wrote:

>On January 19, 2005 at 11:55:43, Rémi Coulom wrote:
>
>>Hi,
>>
>>I am porting my chess program to 64 bit on an AMD64 Athlon processor. I have
>>noticed that, with gcc, sizeof(int)=4. I would have expected sizeof(int)=8. On
>>32-bit platforms, 32-bit variables are faster than 16-bit variables. I wonder if
>>64-bit variables are faster than 32-bit variables on 64-bit machines. I have
>>made a few experiments and did not notice much difference.
>>
>>Rémi
>
>There's some information here:
>
>http://www.devx.com/amd/Article/16101
>
>Longs and pointers are 64 bits. Ints remain 32 bits. You can use -m64 to force a
>64-bit compilation or -m32 to force 32-bit.
>
>I'm afraid that's all I know!
>
>Andrew


Whether longs are 32 or 64 bits depends on the compiler. MSVC8, for example,
keeps int and long the same size (32 bits) and uses __int64 and 'long long' for
the wider variables.


Bo Persson






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