1-bit computing: Difference between revisions

Revision as of 10:12, 17 May 2016

Revision as of 20:01, 21 December 2016

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A '''1-bit''' [[computer architecture]] is an [[instruction set architecture]] for a processor that has [[datapath]] widths and [[processor register|data register]] widths of 1 bit (1/8 [[Octet (computing)|octet]]) wide.

An example of a 1-bit architecture that was actually marketed as a CPU is the [[Motorola MC14500B]] Industrial Control Unit.<ref>{{cite web|publisher=[[Motorola]]|title=MC14500B Industrial Control Unit. Semiconductor Technical Data, Rev. 3|url=http://www.brouhaha.com/~eric/retrocomputing/motorola/mc14500b/mc14500brev3.pdf|year=1995|accessdate=AugustDecember 121, 20122016}}</ref> There are also several design studies for 1-bit architectures in academia, and corresponding 1-bit logic can also be found in programming.

Other examples of 1-bit architectures are [[programmable logic controllers]].

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* [[Logical disjunction|OR]] the value in the 1-bit register with input 2, leaving the result in the register;

* write the value in the 1-bit register to output 1.

This architecture was considered superior when the program makes the decisions rather than performing computations, [[ladder logic]], also for serial data processing.<ref>[http://tinymicros.com/mediawiki/images/e/ec/MC14500B_Handbook.pdf Motorola MC14500B Application Handbook]</ref>

1-bit CPUs can be considered obsolete now, not many kinds have been produced (MC14500B and WDR-1 known) and none known to be available in the major computer component stores ({{as of|2014|lc=y}}, a few on eBay<ref>http://www.ebay.com/itm/Motorola-IC-MC14500B-MC14500BCL-100-NEW-/320837692605</ref>). Finnish company Partco still sells MC14500B as spare part in 2016.<ref>{{cite web |url=http://www.partco.biz/verkkokauppa/product_info.php?products_id=2532&language=en |title=CMOS-LOGIC IC 4500 DIP16 |quote=Also known as MC14500BCP}}</ref>