Explain about two-pass assembler, Computer Engineering

Assignment Help:

Q. Explain about Two-pass assembler?

Assemblers usually make two or more passes through a source program in order to resolve forward references in a program. A forward reference is expressed as a type of instruction in code segment which is referencing the label of an instruction though the assembler hasn't yet encountered the definition of that instruction.

Pass 1:  Assembler reads the whole source program and creates a symbol table of labels and names used in the program that is name of data fields and programs labels and their relative location (offset) within the segment.

Pass 1 concludes the amount of code to be produced for every instruction. 

Pass 2:Assembler uses the symbol table which it constructed in Pass 1. Now it knows the relative position and length of every data field and instruction and it can complete object code for every instruction.  It generates .OBJ (Object file), .LST (list file) and cross reference (.CRF) files.


Related Discussions:- Explain about two-pass assembler

Describe the interpretation features of vba, VBA is licensed to Microsoft a...

VBA is licensed to Microsoft and this compatible with and only Microsoft products. Code written is compiled by an intermediate language known as P-code and this is stored in hostin

How linq is beneficial than stored procedures, There are couple of benefit ...

There are couple of benefit of LINQ over stored procedures.   1. Debugging - It is really very difficult to debug the Stored procedure but as LINQ is part of .NET, you can us

Define electronic data interchange, Electronic Data Interchange (EDI ) is u...

Electronic Data Interchange (EDI ) is used by companies for transactions that happen on regular basis to a pre-determined format. It is one of the electronic commerce technologies.

Or-introduction rule, Or-Introduction : Thus if we know about one thin...

Or-Introduction : Thus if we know about one thing is true, and also we know that a sentence when there thing is in a disjunction is true. Here if we consider example, like we

What are the largest UDP messages, What are the largest UDP messages that c...

What are the largest UDP messages that can fit into single Ethernet frame? UDP utilizes IP for delivery. As ICMP UDP packet is encapsulated in IP datagram. Therefore entire UDP

Fundamentals of systems, System is a word which is derived from the Greek w...

System is a word which is derived from the Greek word 'Systema' which means an organized relationship among components. A System can be defined as orderly grouping of interdepen

Prolog programming language - artificial intelligence, Prolog Programming L...

Prolog Programming Language - Artificial intelligence: Most of the programming languages are procedural: the programmer specifies exactly the correct instructions (algorithms)

Algorithmic complexity theory, Algorithmic Complexity theory: Moreover...

Algorithmic Complexity theory: Moreover a similar situation occurs in broad to specific ILP systems when the inference rules are deductive thus they specialize. So at some sta

Which language is a platform free language, Which language  is a platform ...

Which language  is a platform free language Java language

Differences between datagrid and datalist, Differences between Datagrid, Da...

Differences between Datagrid, Datalist and Repeater?   1. Datagrid has paging while Datalist doesnt. 2. Datalist has a property known as repeat. Direction = vertical/horizon

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