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

Nanoprogramming - computer architecture, Nanoprogramming:  Second c...

Nanoprogramming:  Second compromise: nanoprogramming  it use a 2-level control storage organization  Top level is a vertical format memory  Output of the top level

Explain the use of wire-center have any influence, Does the use of wire-cen...

Does the use of wire-center have any influence on the performance of a token ring? Explain. One problem along with a ring network is as if the cable breaks somewhere, the ring

Illustrate fdma and tdma concepts., Mobile Computing 1. What is Wireles...

Mobile Computing 1. What is Wireless Protocol Requirements and also explain in brief medium access control protocol. 2. Illustrate FDMA and TDMA concepts. 3. What are the

Explain post office protocol, Explain POP (Post Office Protocol). The P...

Explain POP (Post Office Protocol). The Post Office Protocol gives remote access to an electronic mail box. The protocol permits a user's mailbox to reside on a computer which

Registered ports, A) What does this file have? Where was the information in...

A) What does this file have? Where was the information in this file acquired from? What is the information in this file used for? B)  What is the range for popular ports? What i

Explain the generic framework for electronic commerce, Explain the generic ...

Explain the generic framework for electronic commerce along with suitable diagram? Generic Framework for electronic commerce comprises the Applications of EC (as like banking,

How many select lines will have a 16 to 1 multiplexer, How many select line...

How many select lines will a 16 to 1 multiplexer will have ?   Ans. For 16 to 1 MUX four select lines will be needed to select 16 (2 4 ) inputs.

Explain web service - .net component, Can you give an example of when it wo...

Can you give an example of when it would be appropriate to use a web service as opposed to a non-serviced .NET component? Services which help in stock trading by giving analysi

How wap gateway works, How WAP Gateway works? An significant feature of...

How WAP Gateway works? An significant feature of WAP is the maintain of telephony service integrated with micro browsing of data. aveAccess WAP Gateway functionss as a

Modified digital clock, can you deign the schematic of a modified digital c...

can you deign the schematic of a modified digital clock at the gate as well as the IC level and then construct the circuit, lab spec and industral spec?

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