View source for Execution unit

{{Short description|Part of a CPU which performs the operations instructed by the program}}
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In [[computer engineering]], an '''execution unit''' ('''E-unit''' or '''EU''') is a part of a [[Processor (computing)|processing unit]] that performs the operations and calculations forwarded from the [[instruction unit]].<ref>{{Cite web |title=Execution Model Overview |url=https://www.intel.com/content/www/us/en/docs/oneapi/optimization-guide-gpu/2024-1/execution-model.html |access-date=2024-06-23 |website=Intel |language=en}}</ref> It may have its own internal control sequence unit (not to be confused with a [[Central processing unit|CPU]]'s main [[control unit]]), some [[Processor register|register]]s,<ref>{{Cite web |title=AMD Instinct™ MI100 microarchitecture — ROCm Documentation |url=https://rocm.docs.amd.com/en/docs-6.0.0/conceptual/gpu-arch/mi100.html#microarchitecture |access-date=2024-06-23 |website=rocm.docs.amd.com}}</ref> and other internal units such as an [[arithmetic logic unit]],<ref>{{Cite web |title=Intel® Iris® Xe GPU Architecture |url=https://www.intel.com/content/www/us/en/docs/oneapi/optimization-guide-gpu/2023-0/intel-iris-xe-gpu-architecture.html |access-date=2024-06-23 |website=Intel |language=en}}</ref> [[address generation unit]], [[floating-point unit]], [[load–store unit]], [[branch execution unit]]<ref>{{cite web |last=Kanter |first=David |date=November 13, 2012 |title=Intel's Haswell CPU Microarchitecture |url=https://www.realworldtech.com/haswell-cpu/4/ |website=Real World Tech}}</ref> or other smaller and more specific components, and can be tailored to support a certain [[Data type|datatype]], such as [[Integer|integers]] or [[Floating-point arithmetic|floating-points]].<ref>[https://web.archive.org/web/20131231145405/http://people.cs.umass.edu/~weems/CmpSci535/Discussion10.html "Execution Unit" discussion from the University of Massachusetts Amherst], archived on the [[Wayback Machine]]</ref>

It is common for modern processing units to have multiple parallel functional units within its execution units, which is referred to as [[Superscalar processor|superscalar]] design.<ref>{{Cite web |last=Cohen |first=William |date=2016-03-14 |title=Superscalar Execution |url=https://developers.redhat.com/blog/2016/03/14/superscalar-execution |access-date=2024-06-23 |website=Red Hat Developer |language=en}}</ref> The simplest arrangement is to use a single bus manager unit to manage the memory interface and the others to perform calculations. Additionally, modern execution units are usually [[Instruction pipelining|pipelined]].

== References ==
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{{CPU technologies}}
{{Basic computer components}}

[[Category:Central processing unit]]
[[Category:Computer arithmetic]]
[[Category:Superscalar microprocessors| ]]


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