32-bit computing: Difference between revisions

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{{Short description|Computer architecture bit width}}

{{Computer architecture bit widths}}

In [[computer architecture]], '''32-bit computing''' refers to computer systems with a [[Central processing unit|processor]], [[computer memory|memory]], and other major system components that operate on data in a maximum of 32-[[bit]] units.<ref name="PCMProsise1995">{{Cite magazine |last=Prosise |first=Jeff |date=1995-11-07 |title=16 or 32 Bits: Should It Matter to You? |url=https://books.google.com/books?id=qxIpLj9BmV8C&pg=PA321 |magazine=PC Magazine |pages=321–322 |access-date=2022-11-30}}</ref><ref name="SDFEBuchanan1997">{{Cite book |last=Buchanan |first=William |url=https://books.google.com/books?id=ufAQAAAAQBAJ&pg=PA230 |title=Software Development for Engineers : C/C++, Pascal, Assembly, Visual Basic, HTML, Java Script, Java DOS, Windows NT, UNIX. |date=1997 |publisher=Elsevier Science |isbn=978-0-08-054137-2 |___location=Burlington |pages=230 |oclc=854975383}}</ref> Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit [[Personal computer|personal computers]] also have a 32-bit [[address bus]], permitting up to 4 GB&nbsp;[[GiB]] of [[random-access memory|RAM]] to be accessed, far more than previous generations of system architecture allowed.<ref>{{Cite book |last=Venkateswarlu |first=N.B. |title=Essential Computer and IT Fundamentals for Engineering and Science Students |publisher=S. Chand Publishing |year=2012 |isbn=978-81-219-4047-4 |pages=143}}</ref>

32-bit designs have been used since the earliest days of electronic computing, in experimental systems and then in large [[mainframe computer|mainframe]] and [[minicomputer]] systems. The first hybrid 16/32-bit [[microprocessor]], the [[Motorola 68000]], was introduced in the late 1970s and used in systems such as the original [[Apple Macintosh]]. Fully 32-bit microprocessors such as the [[HP FOCUS]], [[Motorola 68020]] and [[i386|Intel 80386]] were launched in the early to mid 1980s and became dominant by the early 1990s. This generation of personal computers coincided with and enabled the first [[History_of_the_InternetHistory of the Internet#1990–2003:_Rise_of_the_global_Internet Rise of the global Internet,_Web_1 Web 1.0|mass-adoption of the World Wide Web]]. While 32-bit architectures are still widely-used in specific applications, the PC and server market has moved on to [[64-bit computing|64 bits]] with [[x86-64]] and other 64-bit architectures since the mid-2000s with installed memory often exceeding the 32-bit 4Gaddress RAMlimit addressof limits4&nbsp;GiB on entry level computers. The latest generation of [[smartphone]]s have also switched to 64 bits.

==Range for storing integers==

A 32-bit [[processor register|register]] can store 2³² different values. The [[range (computer programming)|range]] of [[integer]] values that can be stored in 32 bits depends on the [[Integer (computer science)#Value and representation|integer representation]] used. With the two most common representations, the range is 0 through [[4,294,967,295]] (2³² − 1) for representation as an ([[signedness|unsigned]]) [[binary number]], and −2,147,483,648 (−2³¹) through [[2,147,483,647]] (2³¹ − 1) for representation as [[two's complement]].

One important consequence is that a processor with 32-bit [[memory address]]es can directly access at most 4&nbsp;[[Gibibyte|GiB]] of [[Byte addressing|byte-addressable]] memory (though in practice the limit may be lower).