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

Shell script, shell script to find the factorial of a given number using th...

shell script to find the factorial of a given number using the for loop

Differentiate between sequential and combinational circuits, Problem 1 ...

Problem 1 Prove that :- x(x + y) = x by using identities 2 Write a short note on Analog to Digital Converter (ADC) 3 Differentiate between sequential and combinational ci

What is a parsing, what is parsin? Source programmed statements are ob...

what is parsin? Source programmed statements are observed as tokens, recognizing, building block of language the task of scanning the source statement and classifying the diff

What are kinds of models, What are kinds of models? Class model - Objec...

What are kinds of models? Class model - Objects in the system and their relationships. State model - Life history of the objects. Interaction model - Interactions between

Evaluate fixed execution time, The statement of Gustafson's law can be desc...

The statement of Gustafson's law can be described with the help of an illustration. Let us take a problem, say P, which has to be solved using a parallel computer. Let Ts be the ti

Calculate the shortest distance using minimum spanning tree, Does the minim...

Does the minimum spanning tree of a graph give the shortest distance between any 2 specified nodes? No. The Minimal spanning tree makes sure that the total weight of the tree i

How to define a filename in dos, Q. How to define a Filename in DOS? Ea...

Q. How to define a Filename in DOS? Each file is given a name so that it can be referred to later. This name is termed as Filename. The filename in DOS can be up to eight alpha

Properties of e-cash, Properties: 1.  Monetary Value: Monetary value mu...

Properties: 1.  Monetary Value: Monetary value must be backed by either cash, bank - authorized credit cards or bank certified cashier's cheque. 2.  Interoperability: E-cash

History of parallel computers, History Of Parallel Computers The test ...

History Of Parallel Computers The test with and implementations of the utilize of parallelism started year back in the 1950s by the IBM.  The IBM enlarges computers also calle

Rdbms relational database system, RDBMS relational database system - Re...

RDBMS relational database system - Relational databases are composed of relations and managed through relational operations, and governed through data integrity constraints.

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