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

:P, My name is mrs flo and i apporve dubstep, do you apporve it?

My name is mrs flo and i apporve dubstep, do you apporve it?

Find point-to-point link required in fully connected network, The number of...

The number of point to point links required in a fully connected network for 50 entities is? The number of point to point links needed in a completely connected network for 50

Difference between abstract class and interface, Abstract class: Abstract c...

Abstract class: Abstract classes are the class where one or more methods are abstract but not essentially all method has to be abstract. Abstract methods are the methods, which are

Application to calculate weekly payment of a company, Problem: A compa...

Problem: A company requires a software application to calculate the weekly payment for its employees. The information about the employees (employees' data) is kept in a file.

What is ale and explain the functions of ale in 8085, ALE-> Address latch e...

ALE-> Address latch enable...In the case of microcontroller (8051)& microprocessor 8085 the data line and low order 8 bit address lines are multiplexed. In order to getting address

What are the advantages of using structure in c program, What are the advan...

What are the advantages of using structure in C Program Declaring a struct is a two-stage process. The first stage defines a new data type that has the required structure which

Advantage of a numeric mailbox identifier, Does a numeric mailbox identifie...

Does a numeric mailbox identifier have any advantage over a mnemonic identifier? Explain. Several software systems permit the system administrator to select mailbox names, wher

What is data link layer, Q. What is Data link layer? Data link layer: ...

Q. What is Data link layer? Data link layer: data link layer is responsible for transmitting a group of bits between adjacent nodes. Group of bits is termed as frame. Network

Software architecture of microprocessor, The 68HC11 series is based on the ...

The 68HC11 series is based on the Motorola 6800/1 programming instruction set and hence is a fairly simple 8 bit microprocessor. The internal structure of the 6800/1 is shown below

Carry look-ahead adder and booth''s algorithm, Describe carry look-ahead ad...

Describe carry look-ahead adder? Ans: The input carry required by a stage is directly computed from carry signals obtained from all of the preceding stages i-1,i-2,.....0, rat

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