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Subject: Re: Question to 64 bit experts

Author: Aaron Gordon

Date: 14:27:57 01/19/05

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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

Try using longs instead of ints. I have a DEC Alpha 21164 here (64bit also), and
wondered the same thing. Here is the output I got when running sizeof().

short = 2 (16 bits)
int = 4 (32 bits)
long = 8 (64 bits)
long long = 8 (64 bits)
float = 4 (32 bits)
double = 8 (64 bits)

On my Athlon XP, as expected, I get:
short = 2 (16 bits)
int = 4 (32 bits)
long = 4 (32 bits)
long long = 8 (64 bits)
float = 4 (32 bits)
double = 8 (64 bits)



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