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Subject: Re: Question to 64 bit experts

Author: Andrew Williams

Date: 12:28:19 01/19/05

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On January 19, 2005 at 13:09:41, Bo Persson wrote:

>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

Yes, I'm sorry I should have been more clear. I was talking about gcc, which is
the compiler Remi mentioned in his message. -m32 and -m64 are gcc options.

Regards

Andrew






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