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Fxsave/Fxrstor on Pentium II
Posted: Wed Aug 03, 2005 10:55 am
by Slasher
Hi, I was trying to add FPU/MMX/SSE register saving to my kernel.
Initially I used the Fxsave/Fxrstor commands.
In Bochs this works but on my Pentium II, it does not.
I've used CPUID to check if Fxsave/Fxrstor comands are supported.
Bochs supports it but Pentium II does NOT! it only has MMX
My question is, was the Fxsave/Fxrstor commands introduced after Pentium II (when SSE was introduced) and from which processor will they be present?
Thanks
Re:Fxsave/Fxrstor on Pentium II
Posted: Wed Aug 03, 2005 11:54 am
by FlashBurn
When I?m remembering right they were supported from the 100MHz FSB PII?s. So I think that you use a PII with 66MHz FSB! Take a look at
www.sandpile.org.
Re:Fxsave/Fxrstor on Pentium II
Posted: Wed Aug 03, 2005 1:45 pm
by Slasher
I found a link in Google groups that states Fxsave/Fxrstor works on 333Mhz Pentium II onwards.
Can anyone confirm this?
[url=http://groups-beta.google.com/group/fido7.pvt.hardw.pc.x86.cpu/browse_thread/thread/b9df13f366223382/4a0adf9d227e760b?lnk=st&q=fxsave+pentium+II&rnum=4&hl=en#4a0adf9d227e760b] Google groups link
[/url]
Re:Fxsave/Fxrstor on Pentium II
Posted: Wed Aug 03, 2005 6:49 pm
by AR
Okay, I've looked up the instructions and as far as I can see FXSAVE/FXRSTR were added for SSE, CPUs that don't have SSE will most likely only have FNSAVE/FNRSTR.
Re:Fxsave/Fxrstor on Pentium II
Posted: Thu Aug 04, 2005 1:13 am
by Solar
The "Basic Overview" volume 1 of the Intel CPU Manuals has an overview of which feature was introduced in which processor, IIRC.
Re:Fxsave/Fxrstor on Pentium II
Posted: Thu Aug 04, 2005 4:55 am
by tom1000000
Hi,
I remember checking this out and I thought it was all P2 400MHz and above.
Someone else said 333MHz.
Anyway I am 100% certain it was introduced before P3 / SSE.
Personally I am not supporting any CPU that doesn't have FXSAVE/FSRSTOR.