128-bit

Encyclopedia : 1 : 12 : 128 : 128-bit

This article or section is in need of attention from an expert on the subject.
Please help recruit one, or improve this page yourself}} if you can. See [discussion page] for details.

N-bit Processors
4-bit	8-bit	16-bit	24-bit	31-bit	32-bit	48-bit	64-bit	128-bit
N-bit Applications
		16-bit		31-bit	32-bit		64-bit
N-bit Data Sizes
4-bit	8-bit	16-bit			32-bit		64-bit	128-bit
nibble byte octet word dword qword

In computer architecture, 128-bit integers, memory addresses, or other data units are those that are at most 128 bits wide. Also, 128-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size.

There are currently no mainstream general-purpose processors built to operate on 128-bit integers or addresses, though a number of processors do operate on 128-bit data. System/370, made by IBM, could be considered the first rudimentary 128-bit computer as it used 128-bit floating point registers. Most modern CPUs such as the Pentium and PowerPC have 128-bit vector registers used to store several smaller numbers, such as 4 32-bit floating-point numbers. A single instruction can operate on all these values in parallel (SIMD). They are 128-bit processors in the sense that they have 128-bit registers and in some cases a 128-bit ALU, but they do not operate on individual numbers that are 128 binary digits in length.

Uses

128-bit processors may become prevalent when 2⁶⁴ bytes of addressable memory is no longer enough; however, even if Moore's law were to apply to memory size in the years to come, it would still take a long time to exhaust a 64-bit address space. A doubling of memory capacity requires one extra address bit, so if large servers in 2006 can make use of 512 GB of RAM^{[[Citing sources citation needed]]} (thus requiring 39-bit addresses), then a 64-bit address space would be sufficient for another 50 years. Most supercomputers comprise many 32-bit processors or 64-bit processors linked together, with instructions being executed simultaneously across those processors.

IPV6 is 128 bits wide. Having a processor that can manipulate a 128 bit integer would be useful, since that way the destination IP address can be stored in a register, much as IPV4 is stored now. See also [rfc1924] section 7.

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.