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

Microprocessor and interfacing, Write an ALP to count positve and numbers f...

Write an ALP to count positve and numbers from array.

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

Explain traditional computer clusters, Q. Explain traditional computer clus...

Q. Explain traditional computer clusters? Grid computing employs resources of a lot of separate computers linked by a network (generally internet) to resolve large-scale comput

Difference between packet switching and circuit switching, What are the adv...

What are the advantages and disadvantages of packet switching over circuit switching? The comparison of packet switching and circuit switching demonstrating advantages and disa

What are the disadvantages of bespoke software, What are the disadvantages ...

What are the disadvantages of Bespoke Software -  Very dependent on suppliers of the software; if they go out of business there would be little or no support if problems occ

What is verilog function, What is Verilog function - A function is una...

What is Verilog function - A function is unable to enable a task however functions can enable other functions. - A function would carry out its required duty in zero simula

Adder substractor, how can we bimpliment half substractor using nand gate

how can we bimpliment half substractor using nand gate

Explain about the term false path, Explain about the term false path? How i...

Explain about the term false path? How it find out in circuit? What the effect of false path in circuit? By timing all the paths into the circuit the timing analyzer can find o

What is big endian and little endian format, What is big endian and little ...

What is big endian and little endian format? The name big endian is used when lower byte addresses are used for the more important of the word. The name little endian is used f

Row-major order and column-major order of arrays, Two-dimensional array is ...

Two-dimensional array is represented in memory in following two ways: 1.  Row major representation: To attain this linear representation, the first row of the array is kept in

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