What is assembler, Computer Engineering

Assignment Help:

Q. What is Assembler?

An assembly program is used to transfer assembly language mnemonics to binary code for every instruction after the complete program has been written with support of an editor it's then assembled with help of an assembler. 

An assembler works in 2 stageswhich are: it reads your source code 2 times.  In first pass the assembler gathers all the symbols defined in the program accompanied by their offsets in symbol table.  On the 2ndpass through the source program it generates binary code for every instruction of the program and give all symbols an offset with respect to segment from symbol table.

The assembler produces three files. Object file, list file and cross reference file. The object file comprises the binary code for every instruction in program. It is created only when your program has been successfully assembled without errors.  Errors which are detected by assembler are known as the symbol errors.  For illustrationMOVE AX1, ZX1.

In the statement it reads the word MOVE and it attempts to match with mnemonic sets as there is no mnemonic with this spelling then it presumes it to be an identifier and searches for its entry in symbol table.  It doesn't even find it there hence gives an error as undeclared identifier.

List file is optional and comprises the source code, binary equivalent of every instruction and offsets of symbols in the program.  This file is for purelydocumentation purposes. A number of the assemblers available on PC are TURBO,MASM etc.


Related Discussions:- What is assembler

What is semaphores, What is semaphores?  A semaphore 'S' is a synchroni...

What is semaphores?  A semaphore 'S' is a synchronization tool which is an integer value that, apart from initialization, is accessed only by two standard atomic operations; wa

What is digitizers, What is Digitizers A common device for drawing, pai...

What is Digitizers A common device for drawing, painting, or interactively selecting coordinate positions on an object is a digitizer. These devices can be used to input coordi

ERP, Benefits of implementing ERP

Benefits of implementing ERP

the monte carlo simulation technique, The demand placed on a system is exp...

The demand placed on a system is explained by a lognormally distributed random variable with mean 50 and standard deviation of 10. The capacity of the system is modeled by a Weibul

What is a development class, What is a Development class? Related obje...

What is a Development class? Related objects from the ABAP/4 repository are assigned to the similar development class.  This enables you to right and transport related objects

Explain proces of defining the document page title, Q. Explain proces of de...

Q. Explain proces of defining the Document Page Title? Though the document has a file name, notice it's still labelled Untitled Document; that is because it needs an HTML docum

Define ftp, FTP FTP (File Transfer Protocol) is the protocol used on th...

FTP FTP (File Transfer Protocol) is the protocol used on the Internet for sending files and is usually used for uploading / downloading files (web pages) to and from servers. T

Show the features of hyper-threading, Q. Show the Features of Hyper-threadi...

Q. Show the Features of Hyper-threading? The significant characteristics of hyper threading are: i) Improved response time and reaction, as well as increased number of users

What is centralized spc, What is centralized SPC, what are its modes of ope...

What is centralized SPC, what are its modes of operation? In this centralized control, all the control equipment is replaced through a single processor that must be quite power

Determine about the information centres, Determine about the Information ce...

Determine about the Information centres Airports, supermarkets and any application where information needs to be relayed to customers, gain advantage from having automatic inf

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd