FPU：(Float Point Unit，浮点运算单元)FPU是专用于浮点运算的处理器，以前的FPU是一种单独芯片，在486之后，英特尔把FPU集成在CPU之内。

英文介绍

A floating point unit (FPU) is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Some systems (particularly older, microcode-based architectures) can also perform various transcendental functions such as exponential or trigonometric calculations, though in most modern processors these are done with software library routines.

In most modern general purpose computer architectures, one or more FPUs are integrated with the CPU; however many embedded processors, especially older designs, do not have hardware support for floating point operations.

In the past, some systems have implemented floating point via a coprocessor rather than as an integrated unit; in the microcomputer era, this was generally a single microchip, while in older systems it could be an entire circuit board or a cabinet.

Not all computer architectures have a hardware FPU. In the absence of an FPU, many FPU functions can be emulated, which saves the added hardware cost of an FPU but is significantly slower. Emulation can be implemented on any of several levels - in the CPU as microcode, as an operating system function, or in user space code.

In most modern computer architectures, there is some division of floating point operations from integer operations. This division varies significantly by architecture; some, like the Intel x86 have dedicated floating point registers, while some take it as far as independent clocking schemes.

Floating point operations are often pipelined. In earlier superscalar architectures without general out-of-order execution, floating point operations were sometimes pipelined separately from integer operations. Today, many CPUs/architectures have more than one FPU, such as the PowerPC 970, and processors based on the Netburst and AMD64 architectures (such as the Pentium 4 and Athlon 64, respectively.)

When a CPU is executing a program that calls for a floating-point operation, there are 3 ways to carry it out:

a floating point unit emulator (a floating-point library), add-on FPU and integrated FPU. Most modern computers have integrated FPU hardware.

译文

浮点运算器（英文：floating point unit，简称FPU）是计算机系统的一部分，它是专门用来进行浮点数运算的。典型的运算有加减乘除和开方。一些系统（尤其是比较老的，基于微代码体系的）还可以计算超越函数，例如指数函数或者三角函数，尽管对大多数现在的处理器，这些功能都由软件的函数库完成。

在大多数现在的通用计算机架构中，一个或多个浮点运算器会被集成在CPU（Central Processing Unit，中央处理器）中，但许多嵌入式处理器（特别是比较老的）没有在硬件上支持浮点数运算。

在过去，一些系统通过协同处理器而不在同一个处理器中来处理浮点数。在微型计算机时代，这一般只用一个芯片；而在以前，可能要用一整个电路板甚至一台机箱。

不是所有的计算机架构中都有硬件的浮点运算器。在没有硬件浮点运算器的情况下，许多浮点数的运算也可以像有硬件那样做到。这样可以节省浮点运算器的硬件成本，但这样会使计算变得慢得多。仿硬件浮点运算可以通过多种层次的方法实现——在CPU中用微代码处理，用操作系统的函数处理，用用户自己的代码处理。

在大多数现代计算机的架构中，一些浮点数运算跟整数运算是分开的。这些分别在不同的架构上差别很大。有一些架构，例如英特尔（Intel）的x86处理器设计了浮点数寄存器，另一些架构中，处理浮点数甚至有独立的时频时域。

浮点数运算常常是用特别的总线传输的。在早期的没有中断机制的大尺度架构（的处理器）中，浮点运算有时与整数运算独立传输。今时今日，许多CPU或架构都有超过一个浮点运算器，例如PowerPC 970 和基于Netburst和AMD64架构的处理器（分别例如奔腾（Pentium）4和速龙（Athlon）64）

当CPU执行一个需要浮点数运算的程序时，有三种方式可以执行：软件仿真器（浮点运算函数库）、附加浮点运算器和集成浮点运算器。多数现在的计算机有集成的浮点运算器硬件。