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

Explain the typical functions of operating systems, List the typical functi...

List the typical functions of operating systems. Classical functions of operating system are given as: (1) Process management: A process is a program throughout execution.

What is the use of digital switch, What is the use of digital switch? ...

What is the use of digital switch? Digital switch: This is a device which handles digital signals generated at or passed via a telephone company’s central office further

Digital logic, write a short note on the tri state ttl inverter

write a short note on the tri state ttl inverter

Define usb, Define USB. The Universal Serial Bus(USB) is an industry st...

Define USB. The Universal Serial Bus(USB) is an industry standard developed to give two speed of operation known as low-speed and full-speed. They provide simple, low cost and

What are the advantages of carrying out simulations, What are the Advantage...

What are the Advantages of carrying out simulations -  saves cost (instead of doing the real thing) -  Safer (scenarios tried out on the simulation first before used in real

Explain the effect of cell breathing, Problem : (a) State and describe ...

Problem : (a) State and describe the transmission ranges associated with wireless transmission. Illustrate your answer with a diagram. (b) Sketch a graph representing how a

What is DRAM and what do you understand by DRAM refreshing, What is DRAM? ...

What is DRAM? What do you understand by DRAM refreshing? With the help of a block diagram, demonstrate how DRAM can be interfaced to a microprocessor. Dynamic RAM (DRAM) is bas

C program, #how to write c program for all types of beam reactions

#how to write c program for all types of beam reactions

Linear array-various interconnection networks-fully connecte, Linear Array ...

Linear Array This is a mainly fundamental interconnection pattern.  In this processors are linked in a linear one-dimensional array. The intial and last processors are linked w

Define smtp, SMTP Simple Mail Transfer Protocol, a protocol for sending...

SMTP Simple Mail Transfer Protocol, a protocol for sending e-mail messages among servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from si

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