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

Properties of e-cash, Properties: 1.  Monetary Value: Monetary value mu...

Properties: 1.  Monetary Value: Monetary value must be backed by either cash, bank - authorized credit cards or bank certified cashier's cheque. 2.  Interoperability: E-cash

What are concentrators, What are concentrators? Explain how it helps in con...

What are concentrators? Explain how it helps in connecting number of subscribers. In rural areas, subscribers are usually dispersed. This is both unessential and expensive to g

What is magento, Magento is a feature-rich eCommerce platform built on open...

Magento is a feature-rich eCommerce platform built on open-source technology that gives online merchants with unprecedented flexibility and control over the look, content and funct

C program , minimum number of shelves

minimum number of shelves

What is the meaning of aliasing, a. What is the meaning of aliasing? What a...

a. What is the meaning of aliasing? What are its drawbacks? Describe a method to remove aliasing, using post filtering. b. How can you copy a Pixmap from one place to another

Describe about the digital cameras, Describe about the Digital cameras ...

Describe about the Digital cameras The microprocessor would be used to control the below functions, for instance: - shutter speed - lens focus - Flash - Aperture (l

Advantages of mpi, Advantages of MPI: Every process has its own loc...

Advantages of MPI: Every process has its own local variables It can be used on a broader range of problems than OpenMP It runs on either distributed or shared memor

Algorithms, Design an algorithm (using pseudocode) that takes in as an inpu...

Design an algorithm (using pseudocode) that takes in as an input, two 2-D int arrays that are assumed to be 2 black-and-white images: initialImage x, whose dimensions are IxJ, and

menu-driven program, Write a menu-driven program to change a time in secon...

Write a menu-driven program to change a time in seconds to other units (minutes, hours, etc.).  The main script will loop to continue until the user chooses to exit.  Every time in

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