Data Transfer Instruction

What is the data transfer instruction? Give example.

Data transfer instructions move data between registers or between memory and registers. For example:

• String Forms:

movsb ;move string byte by byte

movsw ;move string word by word

EXAMPLE:

Movsb es, ds ;Copies 8 bits at DS:SI to ES:DI

• New String Form (386+):

movzx ;move string with zero extended

movsx ;move string with sign extended

EXAMPLE:

movsx cx, al ;cl get al

movzx cx,al ;cl gets al

polling in 8085 microprocessor

What do you mean by polling in 8085.

When the microprocessor receives an Interrupt Service Request (ISR) on the interrupt line it must determine which of the devices connected to that input sent the request.

Software Polling is one method by which it can do so.

In Software Polling:

A software routine is used to identify the device requesting service. It does so by checking each device to see if it was the one needing service.

Memory Mapping Scheme

What is the memory mapping scheme? Give any one advantage and disadvantage.

MEMORY MAPPING SCHEME:

WEB MAPPING:

Web mapping is the process of designing, implementing, generating and delivering maps on the World Wide Web and its product.

ADVANTAGE & DISADVANTAGE:

While web mapping primarily deals with technological issues, web cartography additionally studies theoretic aspects: the use of web maps, the evaluation and optimization of techniques and workflows, the usability of web maps, social aspects, and more.

Web maps can easily deliver up to date information. If maps are generated automatically from databases, they can display information in almost realtime. They don't need to be printed, mastered and distributed.

Reliability issues – the reliability of the internet and web server infrastructure is not yet good enough. Especially if a web map relies on external, distributed data sources, the original author often cannot guarantee the availability of the information.

DAD instruction or command

What is a DAD instruction?

DAD - Double Register Add is used to add registers and is used in the assembly programming language.

For example:

Double Add HL to HL

difference between hardware and software interrupts in 8085 microprocessor

Differentiate between hardware interrupts and software interrupts of 8085.

• The software interrupt is initiated by the main program, but the hardware interrupt is initiated by an external device.
• In 8085, the software interrupt cannot be disabled or masked but the hardware interrupt except TRAP can be disabled or masked.