World Library  
Flag as Inappropriate
Email this Article

Instruction register

Article Id: WHEBN0000015072
Reproduction Date:

Title: Instruction register  
Author: World Heritage Encyclopedia
Language: English
Subject: Program counter, Index of computing articles, IR, Instruction cycle, List of AMD Am2900 and Am29000 families, AMD Am2900, CER-12, Instruction unit
Publisher: World Heritage Encyclopedia

Instruction register

In computing, an instruction register (IR) is the part of a CPU's control unit that stores the instruction currently being executed or decoded.[1] In simple processors each instruction to be executed is loaded into the instruction register which holds it while it is decoded, prepared and ultimately executed, which can take several steps.

Some of the complicated processors use a pipeline of instruction registers where each stage of the pipeline does part of the decoding, preparation or execution and then passes it to the next stage for its step. Modern processors can even do some of the steps out of order as decoding on several instructions is done in parallel.

Decoding the opcode in the instruction register includes determining the instruction, determining where its operands are in memory, retrieving the operands from memory, allocating processor resources to execute the command (in superscalar processors), etc.

The output of IR is available to control circuits which generate the timing signals that control the various processing elements involved in executing the instruction.

See also


pl:Wska┼║nik instrukcji
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.