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

Define device interface, Define device interface. The buffer registers ...

Define device interface. The buffer registers DATAIN and DATAOUT and the status flags SIN and SOUT are part of circuitry commonly called as a device interface.

Find 9''s complement for decimal number, Q. Find 9's complement for decimal...

Q. Find 9's complement for decimal number? The 9's complement is achieved by subtracting every digit of number from 9 (the highest digit value). Let's assume that we want to si

Why select clause comes after from clause in linq, The reason is, LINQ is u...

The reason is, LINQ is used with C# or other programming languages, which needs all the variables to be declared first. From clause of LINQ query just describes the range or condit

Set up to use parallel virtual machine, Q. Set up to Use parallel virtual m...

Q. Set up to Use parallel virtual machine? PVM employs two environment variables when starting and running. Each and every PVM user needs to set these two variables to employ P

Give difference between assembler and compiler, Give difference between ass...

Give difference between assembler and compiler. Assembler: It is the translator for an assembly language of computer. An assembly language is a low-level programming language

Classification of pipeline processors, Classification of Pipeline Processor...

Classification of Pipeline Processors In this part, we explain various types of pipelining that can be useful in computer operations. These types depend on the following factor

what is polymorphism in c++, Polymorphism in C++ is the idea that a base c...

Polymorphism in C++ is the idea that a base class can be inherited by various classes. A base class pointer can point to its child class and a base class array can store dissimilar

The need of parallel computation, The Need Of Parallel Computation With...

The Need Of Parallel Computation With the advancement of computer science (CS), computational speed of the processors has also improved many a time. Moreover, there is certain

Select-options and parameters statement , The fields specified by select-op...

The fields specified by select-options and parameters statement cannot be grouped together in the selection screen. No, the fields specified by select-options and parameters s

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