How are comparisons done in 8086 assembly language, Computer Engineering

Assignment Help:

Q. How are comparisons done in 8086 assembly language?

There is a compare instruction CMP. Though this instruction just sets the flags on comparing two operands (both 16 bits and 8 bits). Compare instruction just subtracts value of source from destination without storing result however setting the flag at the time of the process. Normally only 3 comparisons are more important. These are:

Result of comparison    Flag(s) affected

Destination < source    Carry flag = 1

Destination = source    Zero flag = 1

Destination > source    Carry = 0, Zero = 0

Let us look at 3 illustration which show how flags are set when numbers are compared. In illustration 1 BL is less than 10 so carry flag is set. In illustration 2 the zero flag is set since both operands are equal. In illustration 3 the destination (BX) is greater than source so both zero and carry flags are clear.

Example 1: 

 MOV BL, 02h 

 CMP BL, 10h; Carry flag = 1

Example 2:

 MOV AX, F0F0h

 MOV DX, F0F0h

 CMP AX, DX; Zero flag = 1

Example 3:

MOV BX, 200H

CMP BX, 0; Zero and Carry flags = 0


Related Discussions:- How are comparisons done in 8086 assembly language

What is a c++ class, Class is a user-defined data type in C++. It can be fo...

Class is a user-defined data type in C++. It can be formed to solve a particular kind of problem. After creation the user require not know the specifics of the working of a class.

Define the heat transfer processes, Heat Transfer Coursework An interna...

Heat Transfer Coursework An internal combustion engine of a passenger car is operating at steady state conditions e.g. constant speed (r.p.m.) and load (torque), so the engine

What is set screen, SET SCREEN With SET SCREEN the present screen simpl...

SET SCREEN With SET SCREEN the present screen simply specifies the next screen in the chain , control branches to this next screen  as soon as the current screen has been proce

Which objects are independent transport objects, Which objects are independ...

Which objects are independent transport objects? Domains, Data elements, Tables, Technical settings for tables, Secondary indexes for transparent tables, Structures, Views, Ma

Java, what is inheritence and all types in java?

what is inheritence and all types in java?

Two ways of producing a list within a transaction, What are the two ways of...

What are the two ways of producing a list within a transaction? By submitting a separate report. By using leave to list-processing.

Interrupt and scanning method of keypad operation, INTERRUPT METHOD - USING...

INTERRUPT METHOD - USING PORTB CHANGE INTERRUPT By using 4 by 4 matrix keypad connected to PORTA and PORTB. The rows are connected to PORTA-Low (RA1-RA4) and the columns are co

Describe target processor arrangements, Q. Describe target processor arrang...

Q. Describe target processor arrangements? Having seen how to describe one or more target processor arrangements we need to initiate mechanisms for distributing data arrays ove

Explain possible attacks on the wired equivalent privacy, Question : (a...

Question : (a) IEEE802.11 supports two types of network architecture, describe these architectures with the support of diagrams detailing the network components. (b) IEEE80

Define interrupt processing, Q. Define Interrupt Processing? On complet...

Q. Define Interrupt Processing? On completion of execution of an instruction machine checks whether there is any pending interrupt request for interrupts which are enabled. If

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