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

4bit counter using JK flip flop and unique sequence, Need to build a 4bit J...

Need to build a 4bit JK flip flop counter with a unique patter. 6 4 2 5 3 1 F C B A

Which technique allows executing a program not in memory, A set of techniqu...

A set of techniques that allow executing a program which is not entirely in memory is called ? Ans. virtual memory which allows executing a program that is not entirely in me

Data rate limitations in PSTN's by using nyquist theorem, Explain with the ...

Explain with the help of Nyquist theorem, the data rate limitations in PSTN's. Data rates in PSTNs : A voice channel in a public switched telephone network is band restricted

What are the limitations of traditional payment instruments, What are the l...

What are the limitations of traditional payment instruments? The limitations of traditional payment system are that they take a lot of time.  These systems needs manual work to

Discuss program testing and debugging in detail, Discuss program testing an...

Discuss program testing and debugging in detail. In program debugging and testing significant steps are as follows: a. For the program, construction of test data b. Analy

AWS, hosting on aws

hosting on aws

Can a vector have a component equivalent to zero, Q. Can a vector have a co...

Q. Can a vector have a component equivalent to zero and still have a nonzero magnitude? Answer:- Yes For example the 2-dimensional vector (1, 0) has length sqrt (1+0) = 1

Explain the recording mode for web vuser script, We use VuGen to make a Vus...

We use VuGen to make a Vuser script by recording a user performing typical business processes on a customer application. VuGen makes the script by recording the activity among the

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