CPUID (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- freenet.support.CPUInformation.CPUID

public class CPUID
extends Object

Retrieves CPU details via the x86 CPUID instruction through a native JNI library (jcpuid).

This class provides low-level access to CPU identification and feature flags. It loads a platform-specific native library (libjcpuid.so / jcpuid.dll) that executes the CPUID assembly instruction and returns register values.

CPUID Register Layout (Leaf 1, EAX)

 Bits 31:28  Reserved
 Bits 27:20  Extended Family ID
 Bits 19:16  Extended Model ID
 Bits 15:12  Processor Type (Intel only; AMD reserved)
 Bits 11:8   Base Family ID
 Bits 7:4    Base Model ID
 Bits 3:0    Stepping ID

Family/Model Computation

The actual (displayed) family and model are computed as follows:

Actual Family = Base Family + Extended Family (only when Base Family == 0xF for Intel; always for AMD)
Actual Model = Base Model + (Extended Model << 4) (only when Base Family == 0x6 or 0xF for Intel; always for AMD)

AMD Family/Microarchitecture Mapping

AMD Family/Microarchitecture Mapping
Family (hex)	Microarchitecture	Products
15 (0xF)	K8 / Hammer	Athlon 64, Opteron
16 (0x10)	K10	Phenom, Athlon II
20 (0x14)	Bobcat	Ontario, Zacate
21 (0x15)	Bulldozer family	FX, Opteron
22 (0x16)	Jaguar	Kabini, Temash
23 (0x17)	Zen / Zen+ / Zen 2	Ryzen 1000-3000, EPYC 7001-7002
25 (0x19)	Zen 3 / Zen 4	Ryzen 5000-8000, EPYC 7003-9004
26 (0x1A)	Zen 5	Ryzen 9000, EPYC 9005, Ryzen AI 300

AMD Family 19h (Zen 3/4) Model Ranges

 0x00-0x0F  Milan/Chagall      (Zen 3)   - EPYC 7003, Threadripper 5000
 0x10-0x1F  Stones/Storm Peak  (Zen 4)   - EPYC 9004, Threadripper 7000
 0x20-0x2F  Vermeer            (Zen 3)   - Ryzen 5000 desktop
 0x30-0x3F  Badami             (Zen 3)   - EPYC (internal)
 0x40-0x4F  Rembrandt          (Zen 3+)  - Ryzen 6000 mobile
 0x50-0x5F  Cezanne            (Zen 3)   - Ryzen 5000 APU
 0x60-0x6F  Raphael            (Zen 4)   - Ryzen 7000 desktop (AM5)
 0x70-0x77  Phoenix/HawkPoint1 (Zen 4)   - Ryzen 7040/8040 APU
 0x78-0x7F  Phoenix2/HawkPoint2(Zen 4)   - Ryzen 8040 APU
 0xA0-0xAF  Stones-Dense       (Zen 4)   - EPYC 4004/Siena

AMD Family 1Ah (Zen 5) Model Ranges

Sources: LLVM Host.cpp, Linux kernel amd.c, InstLatx64 CPUID dumps.

 0x00-0x0F  Breithorn/Turin        (Zen 5)   - EPYC 9005 server
 0x10-0x1F  Breithorn-Dense        (Zen 5)   - EPYC 9005 dense
 0x20-0x2F  Strix Point            (Zen 5)   - Ryzen AI 300 mobile
 0x30-0x37  Strix Point (2nd)      (Zen 5)   - Ryzen AI 300 mobile
 0x38-0x3F  Strix Point (3rd)      (Zen 5)   - Ryzen AI 300 mobile
 0x40-0x4F  Granite Ridge          (Zen 5)   - Ryzen 9000 desktop (AM5)
 0x50-0x5F  Weisshorn              (Zen 6)   - NOT Zen 5!
 0x60-0x6F  Krackan Point          (Zen 5)   - Ryzen AI 300 mobile
 0x70-0x77  Sarlak/Strix Halo      (Zen 5)   - Ryzen AI Max 300
 0xD0-0xD7  Annapurna              (Zen 5)   - Future EPYC

CPUID Brand String (Most Reliable Identification)

CPUID leaves 0x80000002-0x80000004 return a 48-byte ASCII brand string programmed by AMD/Intel into the CPU. This is the most reliable way to identify a specific CPU model, as model number ranges can overlap across product lines (e.g., model 0x44 is Granite Ridge desktop, not Strix Halo).

See Also:: Wikipedia: CPUID, AMD PPR / CPUID references

Nested Class Summary
Nested Classes
Modifier and Type Class and Description
protected static class CPUID.CPUIDResult
Holds the four 32-bit register values (EAX, EBX, ECX, EDX) returned by a single CPUID instruction call.

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`CPUID.CPUIDResult` Holds the four 32-bit register values (EAX, EBX, ECX, EDX) returned by a single CPUID instruction call.

Constructor Summary
Constructors
Constructor and Description
CPUID()

Constructors
Constructor and Description
`CPUID()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) static int`	`getCPUExtendedFamily()` Returns the Extended Family ID from CPUID leaf 1, EAX bits 27:20.
`(package private) static int`	`getCPUExtendedModel()` Returns the Extended Model ID from CPUID leaf 1, EAX bits 19:16.
`(package private) static int`	`getCPUFamily()` Returns the Base Family ID from CPUID leaf 1, EAX bits 11:8.
`(package private) static int`	`getCPUModel()` Returns the Base Model ID from CPUID leaf 1, EAX bits 7:4.
`(package private) static String`	`getCPUModelName()` Returns the CPU brand string from CPUID extended leaves 0x80000002-0x80000004.
`(package private) static int`	`getCPUStepping()`
`(package private) static int`	`getCPUType()`
`(package private) static String`	`getCPUVendorID()` Returns the 12-byte CPU vendor ID string from CPUID leaf 0.
`(package private) static int`	`getECXCPUFlags()` Return the ECX feature flags
`(package private) static int`	`getEDXCPUFlags()` Return the EDX feature flags
`(package private) static int`	`getExtendedEBXFeatureFlags()`
`(package private) static int`	`getExtendedECXCPUFlags()` Return the extended ECX feature flags
`(package private) static int`	`getExtendedECXFeatureFlags()` There's almost nothing in here.
`(package private) static int`	`getExtendedEDXCPUFlags()`
`static CPUInfo`	`getInfo()` Return information.
`static int`	`getJcpuidVersion()` Return the jcpuid version
`static void`	`main(String[] args)` main.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CPUID
```
public CPUID()
```
- Method Detail
  - getCPUExtendedFamily
```
static int getCPUExtendedFamily()
```
    Returns the Extended Family ID from CPUID leaf 1, EAX bits 27:20.
    To compute the actual family when Base Family == 0xF:
```
   actualFamily = baseFamily + extendedFamily
 
```
    For AMD CPUs, this is always added to the base family.
    Returns:
    Extended Family ID (0-255)
  - getCPUExtendedModel
```
static int getCPUExtendedModel()
```
    Returns the Extended Model ID from CPUID leaf 1, EAX bits 19:16.
    To compute the actual model for CPUs where Base Family is 6 or 0xF:
```
   actualModel = baseModel + (extendedModel << 4)
 
```
    For AMD CPUs, this is always added to the base model.
    Returns:
    Extended Model ID (0-15)
  - getCPUFamily
```
static int getCPUFamily()
```
    Returns the Base Family ID from CPUID leaf 1, EAX bits 11:8.
    WARNING: This is the raw Base Family, NOT the computed family. For AMD CPUs with Base Family == 0xF (15), you must add getCPUExtendedFamily() to get the actual family. For other AMD families (17h, 19h, 1Ah), the extended family is always added to the base family to form the actual family.
    Returns:
    Base Family ID (0-15)
    See Also:
    for the extended family component
  - getCPUModel
```
static int getCPUModel()
```
    Returns the Base Model ID from CPUID leaf 1, EAX bits 7:4.
    WARNING: This is the raw Base Model, NOT the computed model. For CPUs with Base Family == 0x6 or 0xF, you must add getCPUExtendedModel() << 4 to get the actual model. For AMD CPUs, the extended model is always applied when computing the actual model.
    Returns:
    Base Model ID (0-15)
    See Also:
    for the extended model component
  - getCPUModelName
```
static String getCPUModelName()
```
    Returns the CPU brand string from CPUID extended leaves 0x80000002-0x80000004.
    This is the most reliable way to identify a specific CPU model. The brand string is a 48-byte ASCII string programmed by AMD/Intel into the CPU. Examples:
    - "AMD Ryzen 9 9900X 12-Core Processor"
    - "Intel(R) Core(TM) i9-14900K"
    - "AMD EPYC 9754 128-Core Processor"
    IMPORTANT: This is preferred over model-based identification. AMD model number ranges overlap across product lines (e.g., model 0x44 is Granite Ridge desktop, but model ranges can be ambiguous). The brand string is always correct when available.
    Returns:
    CPU brand string, or null if unsupported or native library not loaded
  - getCPUStepping
```
static int getCPUStepping()
```
    Returns:
    0-15
  - getCPUType
```
static int getCPUType()
```
    Returns:
    0-15
  - getCPUVendorID
```
static String getCPUVendorID()
```
    Returns the 12-byte CPU vendor ID string from CPUID leaf 0. The string is constructed from EBX:EDX:ECX (in that order).
    Known vendor strings:
    - "AuthenticAMD" - AMD
    - "GenuineIntel" - Intel
    - "CentaurHauls" - VIA/Centaur
    - "HygonGenuine" - Hygon (AMD-based Chinese JV)
    Returns:
    12-character vendor string, or empty string if native library not loaded
  - getECXCPUFlags
```
static int getECXCPUFlags()
```
    Return the ECX feature flags
  - getEDXCPUFlags
```
static int getEDXCPUFlags()
```
    Return the EDX feature flags
  - getExtendedEBXFeatureFlags
```
static int getExtendedEBXFeatureFlags()
```
  - getExtendedECXCPUFlags
```
static int getExtendedECXCPUFlags()
```
    Return the extended ECX feature flags
  - getExtendedECXFeatureFlags
```
static int getExtendedECXFeatureFlags()
```
    There's almost nothing in here.
  - getExtendedEDXCPUFlags
```
static int getExtendedEDXCPUFlags()
```
  - getInfo
```
public static CPUInfo getInfo()
                       throws UnknownCPUException
```
    Return information.
    Returns:
    the info
    Throws:
    UnknownCPUException
  - getJcpuidVersion
```
public static int getJcpuidVersion()
```
    Return the jcpuid version
    Returns:
    0 if no jcpuid available, 2 if version not supported
  - main
```
public static void main(String[] args)
```
    main.

Class CPUID

CPUID Register Layout (Leaf 1, EAX)

Family/Model Computation

AMD Family/Microarchitecture Mapping

AMD Family 19h (Zen 3/4) Model Ranges

AMD Family 1Ah (Zen 5) Model Ranges

CPUID Brand String (Most Reliable Identification)

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CPUID

Method Detail

getCPUExtendedFamily

getCPUExtendedModel

getCPUFamily

getCPUModel

getCPUModelName

getCPUStepping

getCPUType

getCPUVendorID

getECXCPUFlags

getEDXCPUFlags

getExtendedEBXFeatureFlags

getExtendedECXCPUFlags

getExtendedECXFeatureFlags

getExtendedEDXCPUFlags

getInfo

getJcpuidVersion

main