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

Homework, Use linear activation function and Hebbian learning for a SLFF ne...

Use linear activation function and Hebbian learning for a SLFF network to attempt to learn the following two sets of patterns. Why can the patterns be learned, or why can they not

What are the disadvantages of public key cryptography, What are the disadva...

What are the disadvantages of Public Key Cryptography? Disadvantages of Public Key Cryptography are as given below: a) It is used to encrypt a secret key that is used to e

What is swimlane, What is swimlane? In business model, it is often help...

What is swimlane? In business model, it is often helpful to know which human organization is responsible for activity. Show the partition of activities into columns and lines.

Make a generalized program that accepts a number and base, Q. Make a gener...

Q. Make a generalized program that accepts a number & base, convert it into the given base. Perform necessary validations.

K map explanation, K map explanation for mod 5 up synchronous counter ?

K map explanation for mod 5 up synchronous counter ?

Handshake control of data transfer - computer architecture, Handshake contr...

Handshake control of data transfer during an input operation:   . Handshake control of data transfer during an output operation o   Interface to CPU and Memory o

What is process, In Windows, Thread is a unit of implementation. Process is...

In Windows, Thread is a unit of implementation. Process is the environment in which thread implements. Scheduler, schedules the Threads not the process. In Unix variants, Thread is

Determine about the logical shift, Logical shift A logical shift operat...

Logical shift A logical shift operation transfers 0 through serial input. We apply symbols shl and shr for logical shift left and shift right microoperations, examples:. R1

What is the necessity of an interface, What is the necessity of an interfac...

What is the necessity of an interface?  Any device that has to be linked to a CPU requires an interface. This takes care of the mismatch in speed, data and electrical character

Write the html code to webpage to insert scrollable lists, Write the HTML c...

Write the HTML code to accomplish the web page to insert scrollable lists that will always display four entries of the list. The HTML code to accomplish the web page is given b

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