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

Smart card & e-cash, Smart Card & E-Cash E-cash storable smart cards ca...

Smart Card & E-Cash E-cash storable smart cards can kept and dispense cash electronically, making bills and coins lesser essential. It transfers funds over phone lines, making

What are the super computers, SUPER COMPUTER The upper end of state of ...

SUPER COMPUTER The upper end of state of art mainframe machine is the supercomputer. These  are  the  fastest  machines  in  terms  of  processing  speed  and  use multiprocess

Explain bernstein conditions for detection of parallelism, Bernstein Condit...

Bernstein Conditions for Detection of Parallelism For execution of a number of instructions or a block of instructions in parallel, it must be made certain that instructions ar

Explain the feasibility study, Explain the Feasibility Study This inclu...

Explain the Feasibility Study This includes writing a report to convince management of the merits of adopting proposed new system. Some features of the study comprise: T

What is pci bus, What is PCI bus? The Peripheral component interconnect...

What is PCI bus? The Peripheral component interconnect(PCI) bus is a standard that handles the functions found on a processor bus but in a standardized format that is independe

Illustration of cache size of a system, Q. Illustration of cache size of a ...

Q. Illustration of cache size of a system? Cache Size: Cache memory is very costly as compared to main memory and therefore its size is generally kept very small.  It has bee

Define nondeterministic tm, Define nondeterministic TM?  Arbitraril...

Define nondeterministic TM?  Arbitrarily chooses move when more than one possibility exists Accepts if there is at least one computation that terminates in an acceptin

Explain usenet and newsgroups, Q. Explain Usenet and Newsgroups? In Int...

Q. Explain Usenet and Newsgroups? In Internet there exists another way to meet people and share information. One such way is through Usenet newsgroups. These are special groups

What is gimps native graphics file format, XCF is GIMP's "native" format. T...

XCF is GIMP's "native" format. This will preserve all information about an image, having the layers.

Define a gate fix asic-based design in short, Define a Gate Fix ASIC-based ...

Define a Gate Fix ASIC-based design in short. Gate Fix ASIC-based design: A Gate Fix implies that a select number of gates and their interconnections may be subtracted or ad

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