X64: Difference between revisions
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{{lowercase|title=x64}} |
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'''x64''' is a 64-bit superset of the [[IA-32]] microprocessor architecture. It was originally created by [[Advanced Micro Devices]] (AMD) under the name '''[[AMD64]]''', but has also been adopted by [[Intel Corporation]], which calls its implementation '''[[EM64T]]'''. Since the two implementations were substantially similar (and remain so [[as of 2006]]), [[Microsoft]] coined the term x64 as a vendor-neutral term to name products that support both AMD64 and EM64T. Other companies such as [[Sun Microsystems]] have also adopted this term. |
'''x64''' is a [[64-bit]] superset of the [[IA-32]] microprocessor architecture. It was originally created by [[Advanced Micro Devices]] (AMD) under the name '''[[AMD64]]''', but has also been adopted by [[Intel Corporation]], which calls its implementation '''[[EM64T]]'''. Since the two implementations were substantially similar (and remain so [[as of 2006]]), [[Microsoft]] coined the term x64 as a vendor-neutral term to name products that support both AMD64 and EM64T. Other companies such as [[Sun Microsystems]] have also adopted this term. |
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The "64-bit" designation refers to many aspects of the architecture: the width of the general purpose registers; the widest integer and logical operations supported by the processor; the size of values pushed and popped from the stack; and the width of the pointer data type, or virtual addresses. [[as of 2005|As of December 2005]], current implementations of the x64 architecture only implement the low-order 48 bits of virtual addresses, but pointers are nevertheless 64 bits wide and all 64 bits must be correctly asserted. |
The "64-bit" designation refers to many aspects of the architecture: the width of the general purpose registers; the widest integer and logical operations supported by the processor; the size of values pushed and popped from the stack; and the width of the pointer data type, or virtual addresses. [[as of 2005|As of December 2005]], current implementations of the x64 architecture only implement the low-order 48 bits of virtual addresses, but pointers are nevertheless 64 bits wide and all 64 bits must be correctly asserted. |
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Revision as of 13:31, 15 August 2006
x64 is a 64-bit superset of the IA-32 microprocessor architecture. It was originally created by Advanced Micro Devices (AMD) under the name AMD64, but has also been adopted by Intel Corporation, which calls its implementation EM64T. Since the two implementations were substantially similar (and remain so as of 2006), Microsoft coined the term x64 as a vendor-neutral term to name products that support both AMD64 and EM64T. Other companies such as Sun Microsystems have also adopted this term.
The "64-bit" designation refers to many aspects of the architecture: the width of the general purpose registers; the widest integer and logical operations supported by the processor; the size of values pushed and popped from the stack; and the width of the pointer data type, or virtual addresses. As of December 2005, current implementations of the x64 architecture only implement the low-order 48 bits of virtual addresses, but pointers are nevertheless 64 bits wide and all 64 bits must be correctly asserted.
As there are often at least minor differences in x64 implementations, for instance concerning IOMMU bypass for DMA mapping over 4GB, or additional instructions that might be added in newer processors, the x64 designator alone should only be regarded as signifying generic support for extensions in a product such as an operating system or application software. It is not a guarantee that the product is highly optimized for all specific processor implementations.
Internally, x64 versions of Windows use the AMD64 moniker to designate various components which use 64-bit technology for IA-32 processors (for example, the system folder on a Windows x64 Edition installation CD is named "AMD64" instead of "i386" in 32-bit versions). Similarly, the isalist command in the Solaris Operating System identifies both AMD64- and EM64T-based systems as "amd64", as initial Solaris support for this technology predated the existence of Intel's EM64T extensions and the x64 term.
AMD's original designation for this technology, x86-64, is also used in many places, most notably Linux, to refer collectively to both AMD64 and EM64T.
Microsoft products using the name "x64"
- Windows XP Professional x64 Edition
- Windows Server 2003, Standard x64 Edition
- Windows Server 2003, Enterprise x64 Edition
- Windows Server 2003, Datacenter x64 Edition
- Windows Vista x64 Edition (in development)
- .NET Framework Version 2.0 Redistributable Package x64 (64 Bit)