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Execution unit

From Wikipedia, the free encyclopedia

In computer engineering, an execution unit (E-unit or EU) is a part of a processing unit that performs the operations and calculations forwarded from the instruction unit.[1] It may have its own internal control sequence unit (not to be confused with a CPU's main control unit), some registers,[2] and other internal units such as an arithmetic logic unit,[3] address generation unit, floating-point unit, load–store unit, branch execution unit[4] or other smaller and more specific components, and can be tailored to support a certain datatype, such as integers or floating-points.[5]

It is common for modern processing units to have multiple parallel functional units within its execution units, which is referred to as superscalar design.[6] 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 pipelined.


  1. ^ "Execution Model Overview". Intel. Retrieved 2024-06-23.
  2. ^ "AMD Instinct™ MI100 microarchitecture — ROCm Documentation". rocm.docs.amd.com. Retrieved 2024-06-23.
  3. ^ "Intel® Iris® Xe GPU Architecture". Intel. Retrieved 2024-06-23.
  4. ^ Kanter, David (November 13, 2012). "Intel's Haswell CPU Microarchitecture". Real World Tech.
  5. ^ "Execution Unit" discussion from the University of Massachusetts Amherst, archived on the Wayback Machine
  6. ^ Cohen, William (2016-03-14). "Superscalar Execution". Red Hat Developer. Retrieved 2024-06-23.