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

Programming , Adavantages and disadvantages of compilers and interpreters

Adavantages and disadvantages of compilers and interpreters

Function of osi transport layer, Q. Function of OSI Transport Layer? - ...

Q. Function of OSI Transport Layer? - It takes the information to be sent as well as breaks it into individual packets that are sent and reassembled into a complete message by

Determine the equivalent binary form of decimal number, Solve the equation ...

Solve the equation 23.6 10 = X 2 for X Ans. 23.6 10 = X 2 So as to find X, firstly convert the Decimal number 23.610 in its Binary form. After that take the decimal inte

Goals - artificial intelligence, Goals - artificial intelligence: One ...

Goals - artificial intelligence: One desirable way to make perfect an agent's performance is to enable it to have some details of what it is trying to complete. If it is given

What are preprocessor directives, What are preprocessor directives? Pre...

What are preprocessor directives? Preprocessor directives: These are the commands given to a program called as pre-processor that processes the source code before it passes by

Asembly language programming, Ask question #Minimum Write a program to mask...

Ask question #Minimum Write a program to mask bits D3D2D1D0 and to set bits D5D4 and to invert bits D7D6 of the AX register. 100 words accepted#

Instruction of a micro-program, Q. Instruction of a micro-program? A mi...

Q. Instruction of a micro-program? A micro-instruction is an instruction of a micro-program. It specifies one or more than one micro-operations that can be executed concurrentl

How do subroutines help in program writing, How do subroutines help in prog...

How do subroutines help in program writing? Some of the significant characteristics of Subroutine that help in program writing are: A subroutine is named, each have a

Explain about the e-commerce over extranets, Explain about the e-commerce o...

Explain about the e-commerce over extranets. Extranets are regarding “joining up” the supply chain-suppliers, distributors, resellers and customers are enabling business-to bus

Differentiate between $display and $strobe, Differentiate between $display ...

Differentiate between $display and $strobe These commands have similar syntax, and display text on screen during simulation. $display and $strobe display once every time they a

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