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

The advantages of specifying parameters during instantiation, The advantage...

The advantages of specifying parameters during instantiation method are: -  All values to all the parameters do not need to be specified. Only those parameters that are assigne

Explain the advantages of high level languages, Explain the Advantages of H...

Explain the Advantages of High Level Languages? The major advantage of high-level languages over low-level languages is that they are easier to write, read, and maintain. Ultim

Define asynchronous bus, Define asynchronous bus. Asynchronous buses ar...

Define asynchronous bus. Asynchronous buses are the ones in which every item being transferred is accompanied by a control signal that shows its presence to the destination uni

Define cache line, Define cache line. Cache block is used to refer to a...

Define cache line. Cache block is used to refer to a set of contiguous address location of some size. Cache block is also referred to as cache line.

Find out the correction to be applied in decimal adder, The correction to b...

The correction to be applied in decimal adder to the generated sum is ? Ans. 00110 is the generated sum when the correction to be applied in decimal adder. While the 4 bit su

JAVA, HOW WAS JAVA INVENTED?

HOW WAS JAVA INVENTED?

A digital signature, A digital signature is   encrypting information

A digital signature is   encrypting information

What is e-cash, E-Cash:  E-cash is cash shown by two models. One is the...

E-Cash:  E-cash is cash shown by two models. One is the on-line form of e-cash (introduced by DigiCash) which permits for the completion of all types of internet transactions.

Explain difference between security and protection, Explain difference betw...

Explain difference between Security and Protection? Protection mechanism: The subsequent mechanisms are commonly utilized for protecting files having programs and data. (a

Failures, FAILURES Since reliability engineering is focused on the surv...

FAILURES Since reliability engineering is focused on the survivability or absence of failures, it is more concerned about failures,  understanding  their causes and defining re

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