汇编器在微处理器的验证和应用中举足轻重，如何设计通用的汇编器一直是研究的热点之一。本文提出了一种开放式的汇编器系统设计思想，在汇编语言与机器语言间插入中间代码CMDL（code mapping description language）语言，打破汇编语言与机器语言的直接映射关系，由此建立起一套描述汇编语言与机器语言的开放式映射体系。基于此开放式映射体系开发了一套汇编器系统，具有较高层次上的通用性和可移植性。【关键词】指令集，CMDL，汇编器，开放式 Design of Retargetable Assembler System Liu Ling Feng Wen Nan Wang Ying Chun Jiang An Ping Ji Li Jiu IME of Peking University, 100871【摘要】An assembler plays a very important role in the field of microprocessor verifications and applications, thus how to build a retargetable assembler system has been a hotspot in this field for long time. This paper presents a new method about the retargetable assembler system design.It provides a kind of language CMDL, code mapping description language. During the process of assembling, assembler languages are firstly translated to CMDL, and then mapped to the machine codes. In an other word, CMDL is inserted between assembler languages and machine codes during the translation procedure. As a Medium code, CMDL has a lot of features, such as high extraction, strong descript capabilities. It can describe almost all attributes of assembler languages. By breaking the direct mapping relationship between assembler languages and machine codes, the complexities of machine codes are hided to the users, therefore, the new retargetable assembler system has higher retargetable level by converting the mapping from assembler languages and machine codes to assembler languages and CMDL, and implementationof it becomes easier. Based on the new mapping system structure, a retargetable assemblersystem is developed. It proved the whole system has good retargetability and implantability.【关键词】instruction set, symbol table, assembler, lexical analysis, retargetability
上传时间： 2013-10-10
上传用户：meiguiweishi
基于多点网络的水厂自动监控系统设计Design of MPI Based Automatic Monitoring and Control System in Water Works刘 美 俊(湖南工程学院，湘潭411101)摘要针对水厂工作水泵多、现场离控制站距离远的特点，提出了一种基于MPI多点网络的自动监控系统的设计方法，分析了系统的工作原理，介绍了系统中数据的采集与处理、主站与从站的通信原理以及系统软件的设计。由于这种系统的主、从站PLC之间采用MPI网络通信，具有运行可靠、性能价格比高的特点，所以适用于中小规模水厂的分布式监控场合。关键词多点网络主站从站监控系统Abstract Ina ccordancew ithth efe atuersof w aterw orks,i. e. ，manyp umpsin o perationa ndth ep umps， farfor mt hec ontrolst ation,th em ethodo fdesigninga na utomati(〕monitoringa ndc ontorlsy stemb asedo nM PIis p resented.Th eo perationalpr incipleo fth esy stemi san alyzed,th ed atac olection,data processing; communication between master station and slave station as wel as design and system software are discussed. Because MPI network communicationis used among master station, slave stations and PLC, the system is reliable and high cost-efective. It is， suitable for smal and Mediumsized water works for distrbuted monitoring and control.Keywords MPI Masterst ation Slaves tation Monitoringa ndc ontorlsy stem 自来 水 厂 的自动控制系统一般分为两大部分，一对组态硬件要求较高，投资较大。相对而言，MPI网是水源地深水泵的工作控制，一是水厂区变频恒压供络速度可达187.5 M bps，通过一级中继器传输距离可水控制，两部分的实际距离通常都比较远。某厂水源达Ikm 。根据水厂的具体情况，确定以MPI方式组地有3台深井泵给水厂区的蓄水池供水。水厂区的成网络，主站PLC为S7-300系列的CPU3121FM，从任务是对水池的水进行消毒处理后，通过加压泵向管站为S7-200系列的CPU222。这样既满足了系统要路恒压供水。选用Siemens公司的S7系列可编程控求，又相对于Profibus网络节省了三分之一的成本，制器(PLC)和上位机组成实时数据采集和监控系统， 这种分布式监控系统具有较高的性能价格比。系统对深水泵进行远程控制，对供水泵采用变频器进行恒中PLC的物理层采用RS - 485接口，网络延伸选用压控制以保证整个水厂的电机设备安全、可靠地运带防雷保护的中继器，使系统的安全运行得到了保行。证。MPI网络的拓扑结构如图1所示。1 多点网络(NWI)监控系统的组成Sie me ns 公司S7系列PLC通常有MP」多点网络与Profibus现场总线网络两种组网方式。Profibus现场总线的应用目前较为普遍，通用性较好，它由Profibus一DP, Profibus一FMS, Profibus一PA组成。Profibus - DP型用于分散外设间的数据传输，传输速率为9.6kbps一12Mbps，主要用于现场控制器与分散1/0之间的通信，可满足交直流调速系统快速响应的时间要求，特别适合于加工自动化领域的应用;Profibus - FMS主要解决车间级通信问题，完成中等传输速度的循环或非循环数据交换任务，适用于纺织、楼宇自动化、可编程控制器、低压开关等;Profibus - PA型采用了OSI模型的物理层和数据链路层，适用于过程自动化的总线类型。
上传时间： 2013-10-09
上传用户：fac1003
为提升虚拟仪器传输速率与实时性能，扩展监测范围，在VC的软件平台上设计了一种全功能虚拟示波器。与传统虚拟示波器相比，该系统采用嵌入式系统完成信号采集，采用工业以太网为传输介质，通过线性插值算法和多线程编程思想，实现波形显示、参数计算、频谱分析以及波形存储及回放功能。实验结果表明，该虚拟示波器可以实现20 kHz采样频率下的波形精确显示，达到预期的各项指标。 Abstract: o enhance the transfer rate and real-time of virtual instrument performance， expand scope of monitoring， this paper uses the VCs software platform to design a fully functional virtual oscilloscope. Compared with traditional virtual oscilloscope， this system adopts the embedded system to complete the data acquisition， industrial Ethernet as the transmission Medium used by the linear interpolation algorithm and multi-threaded programming ideas， namely to achieve waveform display， parameter calculation， spectrum analysis and waveform storage and playback. Experimental results show that the virtual oscilloscope can accurately display the waveform with 20kHz sampling frequency， and achieve the desired targets.
上传时间： 2013-11-25
上传用户：wbwyl
The information in this specification is subject to change without notice.Use of this specification for product design requires an executed license agreement from the CompactFlashAssociation.The CompactFlash Association shall not be liable for technical or editorial errors or omissions contained herein; norfor incidental or consequential damages resulting from the furnishing, performance, or use of this material.All parts of the CompactFlash Specification are protected by copyright law and all rights are reserved. Thisdocumentation may not, in whole or in part, be copied, photocopied, reproduced, translated, or reduced to anyelectronic Medium or machine readable form without prior consent, in writing, from the CompactFlash Association.The CFA logo is a trademark of the CompactFlash Association.Product names mentioned herein are for identification purposes only and may be trademarks and/or registeredtrademarks of their respective companies.© 1998-99, CompactFlash Association. All rights reserved.
标签： 技术资料
上传时间： 2013-10-08
上传用户：stewart·
21天学会用JAVA开发网络游戏 书籍语言： 简体中文 书籍类型： 程序设计 授权方式： 免费软件 书籍大小： 287 KB 书籍等级： 整理时间： 2004-11-3 20:41:10 With all of the media attention that is focused on the Internet and the World Wide Web, figuring out exactly what they are all about is sometimes difficult. Are they just a neat new way to market products or will they truly offer us a new Medium of communication that will someday surpass even televisions and telephones? The answer is, who knows? Unfortunately, the ultimate use for the Internet is still unknown. This is because it is still in such a state of flux that it s pretty much impossible to accurately predict where it will end up. However, you can look at the evidence of what is there now and gain some insight into what the Internet might become, at least in terms of games.
上传时间： 2013-12-20
上传用户：天诚24
The extraordinary growth of the World Wide Web has been fueled by the ability it gives authors to easily and cheaply distribute electronic documents to an international audience. As Web documents have become larger and more complex, however, Web content providers have begun to experience the limitations of a Medium that does not provide the extensibility, structure, and data checking needed for large-scale commercial publishing. The ability of Java applets to embed powerful data manipulation capabilities in Web clients makes even clearer the limitations of current methods for the transmittal of document data.
标签： extraordinary the ability authors
上传时间： 2015-08-11
上传用户：ANRAN
这是一个模拟第3类模式地震波的matlab脚本。 This a collection of Matlab scripts that solve the antiplane (mode III) earthquake dynamic problem with slip-weakening friction, on a 1D fault embedded in a 2D homogeneous elastic unbounded Medium. The problem is formulated as a boundary integral equation and the elastodynamic kernels are analytically derived in the spectral domain (spatial wavenumber). The method is explained e.g. by Morrysey and Geubelle (1997), and has been improved and extensively used by Nadia Lapusta, Alain Cochard, etc.
标签： collection antiplane scripts matlab
上传时间： 2013-12-26
上传用户：远远ssad
LCD Driver datasheet The SPF54126A, a 262144-color System-on-Chip (SoC) driver LSI designed for small and Medium sizes of TFT LCD display, is capable of supporting up to 176xRGBx220 in resolution which can be achieved by the designated RAM for graphic data. The 528-channel source driver has true 6-bit resolution, which generates 64 Gamma-corrected values by an internal D/A converter. The source driver of SPFD54126A adopts OP-AMP structure to enhance display quality and it cooperates with advanced circuitry techniques to reduce power consumption.
标签： System-on-Chip datasheet designed Driver
上传时间： 2016-09-22
上传用户：xauthu
IEEE 802.11a-1999 (8802-11:1999/Amd 1:2000(E)), IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications—Amendment 1: High-speed Physical Layer in the 5 GHz band
标签： IEEE 1999 Information Telecommuni
上传时间： 2013-12-24
上传用户：hjshhyy
802.11b-1999/Cor1-2001, IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications—Amendment 2: Higher-speed Physical Layer (PHY) extension in the 2.4 GHz band—Corrigendum1
标签： Telecommunications Information information technology
上传时间： 2013-12-10
上传用户：gxf2016
