Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
x86 Feature Flags
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks
View previous topic :: View next topic  
Author Message
taviso
Retired Dev
Retired Dev


Joined: 15 Apr 2003
Posts: 261
Location: United Kingdom

PostPosted: Tue Jul 15, 2003 3:52 pm    Post subject: x86 Feature Flags Reply with quote

I often see questions on irc like "what does xxx flag mean in /proc/cpuinfo?", or "does xxx flag mean I have this feature?", so ive decided to put together this quick reference.
Search Bait:
Code:
cpuinfo feature flags registers


  • fpu
    Floating Point Unit, the processor contains an FPU that supports the Intel387 floating-point instruction set.
  • vme
    Virtual Mode Extension, the processor supports extensions to virtual-8086 mode.
  • de
    Debugging Extension, the processor supports I/O breakpoints, including debug extensions and DR4/DR5 register trapping.
  • pse
    Page Size Extension, the processor supports 4-Mbyte pages.
  • tsc
    Time Stamp Counter, The RDTSC instruction is supported including access/privilege control.
  • msr
    Model Specific Registers, registers implemented with the RDMSR, WRMSR instructions
  • pae
    Physical Address Extension, Physical addresses greater than 32 bits are supported.
  • mce
    Machine Check Exception, Exception 18, and the CR4.MCE enable bit are supported
  • cx8
    The compare and exchange 8 bytes instruction is supported.
  • apic
    On-chip APIC Hardware Supported, the processor contains a software-accessible Local APIC.
  • sep
    Fast System Call, the processor supports the Fast System Call instructions, SYSENTER and SYSEXIT.
  • mtrr
    Memory Type Range Registers, the Processor supports the Memory Type Range Registers, specifically the MTRR_CAP register.
  • pge
    Page Global Enable, the global bit in the page directory entries (PDEs) and page table entries (PTEs) is supported, indicating TLB entries that are common to different processes and need not be flushed.
  • mca
    The Machine Check Architecture is supported, specifically the MCG_CAP register.
  • cmov
    The processor supports CMOVcc, and if the FPU feature flag (bit 0) is also set, supports the FCMOVCC and FCOMI instructions.
  • pat
    Indicates whether the processor supports the Page Attribute Table. This feature augments the Memory Type Range Registers (MTRRs), allowing an operating system to specify attributes of memory on 4K granularity through a linear address.
  • pse-36
    36-bit Page Size Extension, indicates whether the processor supports 4-Mbyte pages that are capable of addressing physical memory beyond 4GB.
  • pn
    Processor serial number is present and enabled.
  • clflush
    Indicates that the processor supports the CLFLUSH instruction.
  • dts
    Debug Store Indicates that the processor has the ability to write a history of the branch to and from addresses into a memory buffer.
  • acpi
    The processor implements internal MSRs that allow processor temperature to be monitored and processor performance to be modulated in predefined duty cycles under software control.
  • mmx
    The processor supports the MMX technology instruction set extensions to Intel Architecture.
  • fxsr
    Indicates whether the processor supports the FXSAVE and FXRSTOR instructions for fast save and restore of the floating point context.
  • sse
    The processor supports the Streaming SIMD Extensions to the Intel Architecture.
  • sse2
    Indicates the processor supports the Streaming SIMD Extensions - 2 Instructions.
  • ss
    Self Snoop, the processor supports the management of conflicting memory types by performing a snoop of its own cache structure for transactions issued to the bus.
  • ht
    Hyper-Threading Technology, this processor has the capability to operate as multiple logical processors within the same physical package. This field does not indicate that Hyper-Threading Technology has been enabled for this specific processor, only that support is present.
  • tm
    The processor implements the Thermal Monitor automatic thermal control circuit (TCC).

And for AMD users:

  • syscall
    The SYSCALL and SYSRET instructions and associated extensions are supported.
  • mp
    Indicates the processor contains the Athlon MP Model6 extended instructions
  • mmxext
    Indicates the processor supports MMX instruction extensions.
  • 3dnow
    Indicates the processor contains 3dNow! instructions
  • 3dnowext
    Indicates the processor contains 3DNow! instruction extensions

References:
arch/i386/kernel/setup.c
Intel Developer Documentation: Pentium4 Xeon CPUID
AMD developer documentation: BIOS design guide.

_________________
--------------------------------------
Gentoo on Alpha, is your penguin 64bit?
--------------------------------------------------------


Last edited by taviso on Sat Sep 20, 2003 5:27 pm; edited 1 time in total
Back to top
View user's profile Send private message
EugeneTSWong
n00b
n00b


Joined: 18 Sep 2003
Posts: 45

PostPosted: Sat Sep 20, 2003 4:24 am    Post subject: Reply with quote

Thanks. I'm surprised that nobody said anything in this thread.
Back to top
View user's profile Send private message
blue.sca
l33t
l33t


Joined: 28 Aug 2003
Posts: 680
Location: Mainz, Germany

PostPosted: Sat Sep 20, 2003 12:35 pm    Post subject: Reply with quote

thats a nice overview, sad i have so little flags with my athlon ;)
Back to top
View user's profile Send private message
verbatim
Apprentice
Apprentice


Joined: 13 Mar 2003
Posts: 223

PostPosted: Sat Sep 20, 2003 3:48 pm    Post subject: Reply with quote

Thanks for the info. :)

I think one clarification needs to be made though... "mmxext" doesn't indicate the MMX instruction set, it's the same deal as "3dnow" and "3dnowext", with "mmx"=standard MMX, and then "mmxext" for special extensions.
Back to top
View user's profile Send private message
taviso
Retired Dev
Retired Dev


Joined: 15 Apr 2003
Posts: 261
Location: United Kingdom

PostPosted: Sat Sep 20, 2003 5:30 pm    Post subject: Reply with quote

EugeneTSWong wrote:
Thanks. I'm surprised that nobody said anything in this thread.

I had almost forgotten i'd written this, im glad you found it useful! :)

verbatim wrote:
I think one clarification needs to be made though... "mmxext" doesn't indicate the MMX instruction set, it's the same deal as "3dnow" and "3dnowext", with "mmx"=standard MMX, and then "mmxext" for special extensions.

well spotted, i'll update it :)
_________________
--------------------------------------
Gentoo on Alpha, is your penguin 64bit?
--------------------------------------------------------
Back to top
View user's profile Send private message
macslashback
n00b
n00b


Joined: 08 Sep 2003
Posts: 1

PostPosted: Sun Nov 09, 2003 12:52 pm    Post subject: Reply with quote

just what i was lookin for, thanks dude.
Back to top
View user's profile Send private message
mr.twemlow
Tux's lil' helper
Tux's lil' helper


Joined: 12 Nov 2003
Posts: 90
Location: Illinois

PostPosted: Wed Nov 12, 2003 1:18 am    Post subject: questions Reply with quote

does that mean that any athlon supports sse, mmx, mmxext, 3dnow, and 3dnowext? i've got a 2000+ and i'm trying to figure out what flags i can use on it.
Back to top
View user's profile Send private message
beowulf
Apprentice
Apprentice


Joined: 07 Apr 2003
Posts: 225

PostPosted: Wed Nov 12, 2003 7:48 am    Post subject: Reply with quote

Thanks for the info! Wondered about a few of them....

To figure out what cpu flags your cpu supports, you could try this command:
Code:
$ cat /proc/cpuinfo | grep flags

It should return the supported flags....

[edit: fixed a typo /]
_________________
I have nothing witty to say here... ever :-(
Back to top
View user's profile Send private message
mr.twemlow
Tux's lil' helper
Tux's lil' helper


Joined: 12 Nov 2003
Posts: 90
Location: Illinois

PostPosted: Sun Nov 16, 2003 3:03 am    Post subject: Reply with quote

thanks, that worked
_________________
Get Gentoo icons: http://boxturtleme.2ya.com/gentoo-icons.xml

Gentium--A typeface for the nations: https://forums.gentoo.org/viewtopic.php?p=1351563
Back to top
View user's profile Send private message
Genone
Retired Dev
Retired Dev


Joined: 14 Mar 2003
Posts: 9236
Location: beyond the rim

PostPosted: Sun Nov 16, 2003 5:28 am    Post subject: Re: questions Reply with quote

mr.twemlow wrote:
does that mean that any athlon supports sse, mmx, mmxext, 3dnow, and 3dnowext? i've got a 2000+ and i'm trying to figure out what flags i can use on it.

Only Athlon-XPs have sse, but your 2000+ should be ok with sse.
Back to top
View user's profile Send private message
carrotcake
n00b
n00b


Joined: 10 Apr 2004
Posts: 1

PostPosted: Sat Apr 10, 2004 8:01 pm    Post subject: Reply with quote

awesome
Back to top
View user's profile Send private message
Anior
Guru
Guru


Joined: 17 Apr 2003
Posts: 317
Location: European Union (Stockholm / Sweden)

PostPosted: Wed May 18, 2005 10:31 am    Post subject: Reply with quote

Some more flags:

AMD:
nx
Support the No eXecute bit. Making it possible to specify a memory area that only contains data.
lm
Support for Long Mode. AMDs 64 bit extention.

Transmeta:
recovery
Recovery CMS is active (after a bad flash).
longrun
Supports LongRun (shows up even if not activated)
lrti
No idea, please tell me if you know.

Other, add explanations if you're bored:
cxmmx
k6_mtrr
cyrix_arr
centaur_mcr
Back to top
View user's profile Send private message
obrut<-
Apprentice
Apprentice


Joined: 01 Apr 2005
Posts: 183
Location: near hamburg, germany

PostPosted: Tue Jul 25, 2006 5:11 pm    Post subject: Reply with quote

intel and amd:
pni: prescott new instructions aka sse3
Back to top
View user's profile Send private message
roderick
l33t
l33t


Joined: 11 Jul 2005
Posts: 908
Location: St. John's, NL CANADA

PostPosted: Wed Jul 26, 2006 3:33 am    Post subject: Reply with quote

This is great. Bookmarked :)

Here's my flags. Some are not in your list. WOuld be great to know what the others are? (Like nx).

Thanks.

Code:

fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx

_________________
If God were a pickle, I'd still say "no pickle on my burger".
http://roderick-greening.blogspot.com/
Back to top
View user's profile Send private message
pactoo
Guru
Guru


Joined: 18 Jul 2004
Posts: 553

PostPosted: Wed Jul 26, 2006 6:55 am    Post subject: Reply with quote

vmx flag is also missing, indicating vanderpool (also pacifica?) technology
Back to top
View user's profile Send private message
Anior
Guru
Guru


Joined: 17 Apr 2003
Posts: 317
Location: European Union (Stockholm / Sweden)

PostPosted: Fri Jul 28, 2006 9:16 pm    Post subject: Reply with quote

roderick wrote:
Here's my flags. Some are not in your list. WOuld be great to know what the others are? (Like nx).


Taviso went missing in action last October so he's rather unlikely to read this. There are some more flags if you read the complete thread though:

Anior wrote:
Some more flags:

AMD:
nx
Support the No eXecute bit. Making it possible to specify a memory area that only contains data.
...
Back to top
View user's profile Send private message
zietbukuel
l33t
l33t


Joined: 30 Dec 2005
Posts: 606
Location: /dev/peru/lima

PostPosted: Sun Jul 30, 2006 2:50 am    Post subject: Reply with quote

There are my flags:

Code:
fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow pni lahf_lm


8)
_________________
AMD FX 8350 8-core CPU
16GB Corsair Vengeance DDR3 RAM
ASUS M5A97 Motherboard
1TB (Gentoo) + 500GB (Windows 7 for games) HDDs
Nvidia 550 GTX Ti 1Gb Ram DDR5
Cooler Master CM690 Case
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Documentation, Tips & Tricks All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum