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Information about X87

x87 is a math-related instruction subset of the Intel x86 family line of processors. It is so called because initially such instructions were processed by an external chip with a name ending in 87. Like other extensions to the basic processor instruction set, these instructions are not strictly needed to construct working programs, but provide hardware implementation of common mathematical tasks, allowing these tasks to be performed much faster. For example, the x87 instruction set includes instructions to calculate the sine or cosine of a value.

All Intel and AMD processors since the 80486DX have had these instructions built into the main CPU. The term 'x87' is still used to refer to that part of the instruction set that performs conventional floating point operations; compilers may use these instructions to make code that operates faster than if it used library calls to perform floating-point operations.

The x87 instructions are compatible with the IEEE-754 standard for floating-point. However, x87 does not perform operations according to strict IEEE-754 formats, since it uses wide registers internally. A given sequence of arithmetic operations may thus behave differently on a x87 and a processor implementing strict IEEE-754 formats.[1]

Starting from the Pentium 4, the SSE unit implements single-precision, then in later versions double-precision, IEEE-754 formats. The x87 unit is largely deprecated on the 64-bit x86-64 architecture and associated 64-bit implementations of operating systems such as Microsoft Windows, Mac OS X, Solaris, and Linux though it is still well supported for full compatibilty with older applications.

List of x87 generations

References

1. ^ David Monniaux, The pitfalls of verifying floating-point computations, to appear in ACM TOPLAS
  • Intel Corp., IA-32 Intel® Architecture Software Developer's Manual Volume 1: Basic Architecture, order number 253665-017

See also

External link

Intel Corporation

Public (NASDAQ:  INTC , SEHK: 4335 )
Founded 1968 1
Headquarters Santa Clara, California
 United States

Key people Paul S.
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The generic term x86 refers to the "CISC" type instruction set of the most commercially successful CPU architecture[1] in the history of personal computing, used in processors from Intel, AMD, VIA, and others.
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central processing unit (CPU), or sometimes simply processor, is the component in a digital computer capable of executing a program.(Knott 1974) It interprets computer program instructions and processes data.
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The 8087 was the first math coprocessor for 16 bit processors designed by Intel (the I8231 was older but designed for the 8 bit Intel 8080); it was built to be paired with the Intel 8088 and 8086 microprocessors.
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trigonometric functions (also called circular functions) are functions of an angle. They are important in the study of triangles and modeling periodic phenomena, among many other applications.
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trigonometric functions (also called circular functions) are functions of an angle. They are important in the study of triangles and modeling periodic phenomena, among many other applications.
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486
Central processing unit

The exposed die of an Intel 80486DX2 microprocessor.
Produced: From 1989 to 2007
Common Manufacturers:
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compiler is a computer program (or set of programs) that translates text written in a computer language (the source language) into another computer language (the target language).
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Pentium 4
Central processing unit

An LGA 775 Pentium 4
Produced: From 2000 to 2008
Manufacturer: Intel
CPU Speeds: 1.3 GHz to 3.
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The term SSE may refer to:

In Computing:
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x86-64 is a 64-bit superset of the x86 instruction set architecture. The x86-64 instruction set natively supports Intel's x86 and was designed by Advanced Micro Devices (AMD), who have since renamed it AMD64.
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Microsoft Windows

Screenshot of Windows Vista Ultimate, the latest version of Microsoft Windows.
Company/developer: Microsoft Corporation
OS family: MS-DOS/9x-based, Windows CE, Windows NT
Source model: Closed source

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Mac OS X (IPA: /mæk.oʊ.ɛs.tɛn/) is a line of graphical operating systems developed, marketed, and sold by Apple Inc., the latest of which is pre-loaded on all currently shipping Macintosh computers.
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The Solaris Operating System, usually known simply as Solaris, is a computer operating system developed by Sun Microsystems. It is certified against the Single Unix Specification as a version of Unix, and although historically a closed-source product, a majority of
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Linux (pronunciation: IPA: /ˈlɪnʊks/, lin-uks) is a Unix-like computer operating system. Linux is one of the most prominent examples of free software and open source development; its underlying source code can be
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The 8087 was the first math coprocessor for 16 bit processors designed by Intel (the I8231 was older but designed for the 8 bit Intel 8080); it was built to be paired with the Intel 8088 and 8086 microprocessors.
..... Click the link for more information.
The Intel 80287 ('287') was the math coprocessor for the Intel 80286 series of microprocessors. It was used to perform floating point arithmetic operations directly in hardware and ran at two thirds (2/3) the speed of the 286 CPU.
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The Intel's i387 ("387") was the math coprocessor for the Intel386 series of microprocessors, and the first Intel coprocessor to implement the IEEE 754 standard in every detail. It was used to perform floating point arithmetic operations directly in hardware.
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The Intel's i487 is a floating point unit coprocessor for Intel i486SX machines. It was essentially a full-blown i486DX chip. When installed into an i486SX system, the i487 disabled the main CPU and took over all CPU operations.
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486
Central processing unit

The exposed die of an Intel 80486DX2 microprocessor.
Produced: From 1989 to 2007
Common Manufacturers:
..... Click the link for more information.
NexGen (Milpitas, CA) was a private semiconductor company that designed x86 PC central processing units until it was purchased by AMD in 1996. Like competitor Cyrix, NexGen was a fabless design house that designed its chips but relied on other companies for production.
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Intel Corporation

Public (NASDAQ:  INTC , SEHK: 4335 )
Founded 1968 1
Headquarters Santa Clara, California
 United States

Key people Paul S.
..... Click the link for more information.
The generic term x86 refers to the "CISC" type instruction set of the most commercially successful CPU architecture[1] in the history of personal computing, used in processors from Intel, AMD, VIA, and others.
..... Click the link for more information.
MMX is a SIMD instruction set designed by Intel, introduced in 1997 in their Pentium line of microprocessors, designated as "Pentium with MMX Technology".[1][2] It developed out of a similar unit first introduced on the Intel i860.
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SSE2, Streaming SIMD Extensions 2, is one of the IA-32 SIMD (Single Instruction, Multiple Data) instruction sets. SSE2 was first introduced by Intel with the initial version of the Pentium 4 in 2001.
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SSE3, also known by its Intel code name Prescott New Instructions (PNI), is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU.
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3DNow! is the name of a multimedia extension created by AMD for its processors, starting with the K6-2 in 1998. It is an addition of SIMD instructions to the traditional x86 instruction set, designed to improve a CPU's ability to perform the vector processing requirements of many
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Flynn's Taxonomy
  Single
Instruction Multiple
Instruction
Single
Data SISD MISD
Multiple
Data SIMD MIMD In computing, SIMD (Single Instruction, Multiple D
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