# core.cpuid

Identify the characteristics of the host CPU, providing information about cache sizes and assembly optimisation hints.
References:
Some of this information was extremely difficult to track down. Some of the documents below were found only in cached versions stored by search engines! This code relies on information found in:

- "Intel(R) 64 and IA-32 Architectures Software Developers Manual, Volume 2A: Instruction Set Reference, A-M" (2007).
- "AMD CPUID Specification", Advanced Micro Devices, Rev 2.28 (2008).
- "AMD Processor Recognition Application Note For Processors Prior to AMD Family 0Fh Processors", Advanced Micro Devices, Rev 3.13 (2005).
- "AMD Geode(TM) GX Processors Data Book", Advanced Micro Devices, Publication ID 31505E, (2005).
- "AMD K6 Processor Code Optimisation", Advanced Micro Devices, Rev D (2000).
- "Application note 106: Software Customization for the 6x86 Family", Cyrix Corporation, Rev 1.5 (1998)
- www.datasheetcatalog.org/datasheet/nationalsemiconductor/GX1.pdf
- "Geode(TM) GX1 Processor Series Low Power Integrated X86 Solution", National Semiconductor, (2002)
- "The VIA Isaiah Architecture", G. Glenn Henry, Centaur Technology, Inc (2008).
- http://www.sandpile.org/ia32/cpuid.htm
- www.akkadia.org/drepper/cpumemory.pdf
- "What every programmer should know about memory", Ulrich Depper, Red Hat, Inc., (2007).
- "CPU Identification by the Windows Kernel", G. Chappell (2009). http://www.geoffchappell.com/viewer.htm?doc=studies/windows/km/cpu/cx8.htm
- "Intel(R) Processor Identification and the CPUID Instruction, Application Note 485" (2009).

BUGS:
Currently only works on x86 and Itanium CPUs. Many processors have bugs in their microcode for the CPUID instruction, so sometimes the cache information may be incorrect.
License:
Boost License 1.0
Authors:
Don Clugston, Tomas Lindquist Olsen <tomas@famolsen.dk>
Source:

struct CacheInfo;
  Cache size and behaviour
  uint size;
    Size of the cache, in kilobytes, per CPU. For L1 unified (data + code) caches, this size is half the physical size. (we don't halve it for larger sizes, since normally data size is much greater than code size for critical loops).
  ubyte associativity;
    Number of ways of associativity, eg: 1 = direct mapped 2 = 2-way set associative 3 = 3-way set associative ubyte.max = fully associative
  uint lineSize;
    Number of bytes read into the cache when a cache miss occurs.
string vendor();
  Returns vendor string, for display purposes only. Do NOT use this to determine features! Note that some CPUs have programmable vendorIDs.
string processor();
  Returns processor string, for display purposes only
CacheInfo[5u] datacache;
  The data caches. If there are fewer than 5 physical caches levels, the remaining levels are set to uint.max (== entire memory space)
bool x87onChip();
  Does it have an x87 FPU on-chip?
bool mmx();
  Is MMX supported?
bool sse();
  Is SSE supported?
bool sse2();
  Is SSE2 supported?
bool sse3();
  Is SSE3 supported?
bool ssse3();
  Is SSSE3 supported?
bool sse41();
  Is SSE4.1 supported?
bool sse42();
  Is SSE4.2 supported?
bool sse4a();
  Is SSE4a supported?
bool amd3dnow();
  Is AMD 3DNOW supported?
bool amd3dnowExt();
  Is AMD 3DNOW Ext supported?
bool amdMmx();
  Are AMD extensions to MMX supported?
bool hasFxsr();
  Is fxsave/fxrstor supported?
bool hasCmov();
  Is cmov supported?
bool hasRdtsc();
  Is rdtsc supported?
bool hasCmpxchg8b();
  Is cmpxchg8b supported?
bool hasCmpxchg16b();
  Is cmpxchg8b supported?
bool hasSysEnterSysExit();
  Is SYSENTER/SYSEXIT supported?
bool has3dnowPrefetch();
  Is 3DNow prefetch supported?
bool hasLahfSahf();
  Are LAHF and SAHF supported in 64-bit mode?
bool hasPopcnt();
  Is POPCNT supported?
bool hasLzcnt();
  Is LZCNT supported?
bool isX86_64();
  Is this an Intel64 or AMD 64?
bool isItanium();
  Is this an IA64 (Itanium) processor?
bool hyperThreading();
  Is hyperthreading supported?
uint threadsPerCPU();
  Returns number of threads per CPU
uint coresPerCPU();
  Returns number of cores in CPU
bool preferAthlon();
  Optimisation hints for assembly code. For forward compatibility, the CPU is compared against different microarchitectures. For 32-bit X86, comparisons are made against the Intel PPro/PII/PIII/PM family.
  The major 32-bit x86 microarchitecture 'dynasties' have been: (1) Intel P6 (PentiumPro, PII, PIII, PM, Core, Core2). (2) AMD Athlon (K7, K8, K10). (3) Intel NetBurst (Pentium 4, Pentium D). (4) In-order Pentium (Pentium1, PMMX, Atom) Other early CPUs (Nx586, AMD K5, K6, Centaur C3, Transmeta, Cyrix, Rise) were mostly in-order. Some new processors do not fit into the existing categories: Intel Atom 230/330 (family 6, model 0x1C) is an in-order core. Centaur Isiah = VIA Nano (family 6, model F) is an out-of-order core.
  Within each dynasty, the optimisation techniques are largely identical (eg, use instruction pairing for group 4). Major instruction set improvements occur within each dynasty. Does this CPU perform better on AMD K7 code than PentiumPro..Core2 code?
bool preferPentium4();
  Does this CPU perform better on Pentium4 code than PentiumPro..Core2 code?
bool preferPentium1();
  Does this CPU perform better on Pentium I code than Pentium Pro code?
uint stepping;
  Processor type (vendor-dependent). This should be visible ONLY for display purposes.
uint model;
  Processor type (vendor-dependent). This should be visible ONLY for display purposes.
uint family;
  Processor type (vendor-dependent). This should be visible ONLY for display purposes.

Page generated by Ddoc. Copyright Don Clugston 2007 - 2009.