Editing X86 (section)

{{Short description|Family of instruction set architectures}}
{{About|the Intel microprocessor architecture in general|the 32-bit generation of this architecture that is also referred to as "x86"|IA-32}}
{{Use mdy dates|date=June 2016}}
{{Lowercase title}}
{{Infobox CPU architecture
| name       = x86
| designer   = [[Intel]], [[Advanced Micro Devices|AMD]]
| bits       = [[16-bit computing|16-bit]], [[32-bit computing|32-bit]] and [[64-bit computing|64-bit]]
| introduced = 1978 (16-bit), 1985 (32-bit), 2003 (64-bit)
| version    =
| design     = [[Complex instruction set computer|CISC]]
| type       = [[Register–memory architecture|Register–memory]]
| encoding   = Variable (1 to 15 bytes)
| branching  = [[Status register|Condition code]]
| endianness = Little
| page size  = [[8086]]–[[i286]]: None<br/>[[Intel 386|i386]], [[Intel 486|i486]]: 4&nbsp;KB pages<br/>[[P5 (microarchitecture)|P5]] [[Pentium]]: added 4&nbsp;MB pages<br/>(Legacy [[Physical Address Extension|PAE]]: 4&nbsp;KB→2&nbsp;MB)<br/>[[Long mode|x86-64]]: added 1&nbsp;GB pages
| extensions = [[x87]], [[IA-32]], [[x86-64]], [[MMX (instruction set)|MMX]], [[3DNow!]], [[Streaming SIMD Extensions|SSE]], [[Machine Check Architecture|MCA]], [[Advanced Configuration and Power Interface|ACPI]], [[SSE2]], [[NX bit]], [[simultaneous multithreading|SMT]], [[SSE3]], [[SSSE3]], [[SSE4]], [[SSE4.2]], [[AES-NI]], [[CLMUL instruction set|CLMUL]], [[SM3 (hash function)|SM3]], [[SM4 (cipher)|SM4]], [[RDRAND]], [[Intel SHA extensions|SHA]], [[Intel MPX|MPX]], [[Secure Memory Encryption|SME]], [[Software Guard Extensions|SGX]], [[XOP instruction set|XOP]], [[F16C]], [[Intel ADX|ADX]], [[Bit Manipulation Instruction Sets|BMI]], [[FMA instruction set|FMA]], [[Advanced Vector Extensions|AVX]], [[AVX2]], [[AVX-VNNI]], [[AVX512]], [[AVX10]], [[Advanced Matrix Extensions|AMX]], [[VT-x]], [[VT-d]], [[AMD-V]], [[AMD-Vi]], [[Transactional Synchronization Extensions|TSX]], [[Advanced Synchronization Facility|ASF]], [[Trusted Execution Technology|TXT]], [[Advanced Performance Extensions|APX]]
| open       = Partly. For some advanced features, x86 may require license from Intel, though some do not need it;{{cn|date=December 2024}} x86-64 may require an additional license from AMD. The [[Pentium Pro]] processor (and [[NetBurst]]) has been on the market for more than 21 years<ref>{{cite press release |last=Pryce |first=Dave |date=May 11, 1989 |title=80486 32-bit CPU breaks new ground in chip density and operating performance. (Intel Corp.) (product announcement) EDN}}</ref> and so cannot be subject to patent claims. The [[i686]] subset of the x86 architecture is therefore fully open. The [[Opteron]] 1000 series processors have been on the market for more than 21 years<ref>{{cite web|url=https://www.hpcwire.com/2003/09/12/amd-announces-new-amd-opteron-processors/ |last=Swoyer |first=Stephen |date=April 24, 2003 |title=AMD introduces 64-bit Opteron Chip (ESJ) (news article)}}</ref> and so cannot be subject to patent claims. The [[AMD K8]] subset of the x86 architecture is therefore fully open.
| gpr        = {{blist|16-bit: 6&nbsp;semi-dedicated registers, BP and SP are not general-purpose|32-bit: 8&nbsp;GPRs, including EBP and ESP|64-bit: 16&nbsp;GPRs, including RBP and RSP}}
| fpr        = {{blist|16-bit: optional separate [[x87]] FPU|32-bit: optional separate or integrated [[x87]] FPU, integrated [[Streaming SIMD Extensions|SSE]] units in later processors|64-bit: integrated [[x87]] and [[SSE2]] units, later implementations extended to [[AVX2]] and [[AVX512]]}}
}}

'''x86''' (also known as '''80x86'''<ref>{{cite book |last1=Rao |first1=P.V.S. |title=Computer System Architecture |date=2009 |publisher=Prentice-Hall of India |isbn=978-81-203-3594-3 |page=402 (Section 19.1, ''The x86 family of processors'')}}</ref> or the '''8086 family''')<ref>{{cite book |last1=Mhatre |first1=Swapneel Chandrakant |title=Microprocessors and Interfacing Techniques: For S. E. (Computer Engineering) Semester II of University of Pune |date=2012 |publisher=Jaico Publishing House |isbn=978-81-8495-325-1}}</ref> is a family of [[complex instruction set computer]] (CISC) [[instruction set architecture]]s{{Efn|Unlike the [[microarchitecture]] (and specific electronic and physical implementation) used for a specific microprocessor design.}} initially developed by [[Intel]], based on the [[Intel 8086|8086]] microprocessor and its 8-bit-external-bus variant, the [[Intel 8088|8088]]. The 8086 was introduced in 1978 as a fully [[16-bit computing|16-bit]] extension of [[8-bit computing|8-bit]] Intel's [[Intel 8080|8080]] microprocessor, with [[x86 memory segmentation|memory segmentation]] as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the [[Intel 80186|80186]], [[Intel 80286|80286]], [[i386|80386]] and [[i486|80486]]. Colloquially, their names were "186", "286", "386" and "486".

The term is not synonymous with [[IBM PC compatible|IBM PC compatibility]], as this implies a multitude of other [[computer hardware]]. [[Embedded system]]s and general-purpose computers used x86 chips [[Influence of the IBM PC on the personal computer market#Before the IBM PC's introduction|before the PC-compatible market started]],{{Efn|The [[GRID Compass]] laptop, for instance.}} some of them before the [[IBM PC]] (1981) debut.

{{As of|2022|06}}, most [[desktop computer|desktop]] and [[laptop]] computers sold are based on the x86 architecture family,<ref>{{cite web|url=https://www.tomshardware.com/news/intel-amd-4q-2021-2022-market-share-desktop-notebook-server-x86|title=AMD Sets All-Time CPU Market Share Record as Intel Gains in Desktop and Notebook PCs|first=Paul|last=Alcorn|date=February 9, 2022|website=[[Tom's Hardware]]}}</ref> while mobile categories such as [[smartphone]]s or [[tablet computer|tablets]] are dominated by [[ARM architecture|ARM]]. At the high end, x86 continues to dominate computation-intensive [[workstation]] and [[cloud computing]] segments.<ref>{{cite web |url=https://icloud.pe/blog/the-cloud-beyond-x86-how-old-architectures-are-making-a-comeback/ |title=The cloud beyond x86: How old architectures are making a comeback |last1=Brandon |first1=Jonathan |date=15 April 2015 |website=ICloud PE |publisher=Business Cloud News |access-date=23 November 2020 |quote=Despite the dominance of x86 in the datacentre it is difficult to ignore the noise vendors have been making over the past couple of years around non-x86 architectures like ARM... |archive-date=August 19, 2021 |archive-url=https://web.archive.org/web/20210819235820/https://icloud.pe/blog/the-cloud-beyond-x86-how-old-architectures-are-making-a-comeback/ |url-status=live }}</ref>

<gallery>
File:KL Intel D8086.jpg|The x86 architectures were based on the Intel 8086 microprocessor chip, initially released in 1978.
File:Intel Core i7 13700K.jpg|Intel Core i7, a modern x86-compatible, 64-bit multicore processor
File:Slot-A Athlon.jpg|AMD Athlon (early version), a technically different but fully compatible x86 implementation
</gallery>