Re: [gentoo-user] Detecting 64 bit Intel chips

[Alan McKinnon]

On Wednesday 05 March 2008, Chris Brennan wrote:
> Here is the output of my cpuinfo, I'll point out where it will mean
> 64bit. For the sake of this demonstration, I have only pasted one (1)
> CPU.
>
> model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ <-- Here
> will be your first indication. 64 bit processors, weather they are
> SPARC, AMD or intel, must identify themselves clearly in the model
> name field.

In my case "must" equates to "should. but doesn't"
The box on my desk identifies the cpu as Pentium4. But it's running 64 
bit SLES, so something got omitted on the chip

> flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
> cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
> fxsr_opt rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm
> cmp_legacy svm extapic cr8_legacy <-- you can look for flags that may
> give away 64bit, such as lahf_lm, lm and nx.

Is there a list somewhere of which flags are definitely 64 bit 
capabilities only, and which might be found on 32 bit chips?

It would not surprise me if a manufacturer announced they had 
implemented ssse3 on 32 bit silicon for example

> address sizes	: 40 bits physical, 48 bits virtual

How about this? Current amd64 implements 48 bit addressing, how wide is 
it for 32 bit? OTOH my Core2 Duo notebook does not have this field at 
all

> For reference, this is a good read talking about 64 Bit processors
> and how to identify them. http://en.wikipedia.org/wiki/X86-64

I see it's vastly more complex than I ever imagined. Thanks for the link 
though, learned a lot!

-- 
Alan McKinnon
alan dot mckinnon at gmail dot com

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