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

Define modem, Define Modem. A modem changes digital signals into audio ...

Define Modem. A modem changes digital signals into audio tones to be transmitted over telephone lines and also changes audio tones from the lines in digitals signals for machin

State any three properties of the neutrons, Q. State any three properties o...

Q. State any three properties of the neutrons. (i) A Neutrons are the constituent particles of all nuclei except hydrogen. (ii) As they are neutral particles they aren't de

Prototyping and incremental development, a) Write  the main differences amo...

a) Write  the main differences among prototyping and incremental development.    b) Explain the commonality and main differences among agile approach and RUP.

Stepwise refinement of the program, What do you understand by stepwise refi...

What do you understand by stepwise refinement of the program? The method of "Stepwise refinement" means to take an object and move it from a general perspective to a exact leve

What do you mean by digital computer, COMPUTER ORGANIZATION & ARCHITECTURE ...

COMPUTER ORGANIZATION & ARCHITECTURE 1. What do you mean by digital computer? Explain the block diagram of a digital computer. 2. What do you mean by Difference Engine? Expl

Write statement, Rounding off of values can be carried out using the write ...

Rounding off of values can be carried out using the write statement. Yes, Rounding off value can be out by using the write statement.

Components of flash, A piece of art can be looked at as having 3 main compo...

A piece of art can be looked at as having 3 main components, the subject, the composition and the content. Subject The subject of an artwork is, in simple terms, the object

Where does the cpu enhanced mode originate , Intel's 8086 was the first 32-...

Intel's 8086 was the first 32-bit processor, and as the company had to backward-support the 8086. All the modern Intel-based processors will run in the Enhanced mode, capable of sw

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