In computer architecture, 32-bit integers, memory addresses, or other data units are those that are at most 32 bits (4 octets) wide. Also, 32-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. 32-bit is also a term given to a generation of microcomputers in which 32-bit microprocessors are the norm.

A 32-bit register can store 2³² different values. The signed range of integer values that can be stored in 32 bits is -2147483648 through 2147483647 (unsigned: 0 through 4,294,967,295). Hence, a processor with 32-bit memory addresses can directly access 4 GiB of byte-addressable memory.

The external address and data buses are often wider than 32 bits but both of these are stored and manipulated internally in the processor as 32-bit quantities. For example, the Pentium Pro processor is a 32-bit machine, but the external address bus is 36 bits wide, and the external data bus is 64 bits wide.^[1]

Architecture [edit]

Prominent 32-bit instruction set architectures used in general-purpose computing include the IBM System/360 and its 32-bit successors, the DEC VAX, the NS320xx, the Motorola 68k, the Intel IA-32 32-bit version of the x86 architecture, and the 32-bit versions of the ARM, SPARC, MIPS, PowerPC and PA-RISC architectures. 32-bit instruction set architectures used for embedded computing include the 68k and ColdFire, x86, ARM, MIPS, PowerPC, and Infineon TriCore architectures.

Images [edit]

In digital images/pictures, 32-bit can refer to 24-bit truecolor images with an 8-bit alpha channel.

Alternatively it may refer to 32-bit per channel rather than 24-bit colour + 8-bit alpha. 32-bit per channel images are used to represent values brighter than white; these values can then be used to more accurately retain bright highlights when either lowering the exposure of the image or when it is seen through a dark filter or dull reflection.

An example of this is the reflection seen in an oil slick; even though the reflection is only a fraction of that seen in a mirror surface, the reflection of highlights can still be seen as bright white areas, not dull grey shapes.

32-bit file format [edit]

A 32-bit file format is a binary file format for which each elementary information is defined on 32 bits (or 4 Bytes). An example of such a format is the Enhanced Metafile Format.

See also [edit]

• 16-bit
• 16-bit application
• 32-bit application
• 64-bit
• History of video games (32-bit era)
• Word (data type)
• Physical Address Extension (PAE)

References [edit]

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2009)

External links [edit]

• HOW Stuff Works "How Bits and Bytes work"
• Ken Colburn on LockerGnome.com: 32-Bit Vs. 64-Bit Windows