Describe program control instructions, Computer Engineering

Assignment Help:

Q. Describe Program Control Instructions?

These instructions specify conditions for altering the sequence of program execution or we can say in other words that the content of PC (program counter) register.  PC points to memory location which holds the subsequent instruction to be executed. The alteration in value of PC as a result of execution of control instruction such as BRANCH or JUMP causes a break in sequential execution of instructions. The most common control instructions are as following:

JUMP and BRANCH may be unconditional or conditional. JUMP is an unconditional branch used to implement simple loops. JNE jump not equal is conditional branch instruction. The conditional branch instructions like BRP X and BRN X causes a branch to memory location X if the result of most recent operation is positive or negative correspondingly. If the condition is true PC is loaded with branch address X and next instruction is taken from X otherwise PC is not changed and the subsequent instruction is taken from location pointed by PC. Figure below displays an unconditional branch instruction and a conditional branch instruction if content of AC is zero.

MBR←0; Assign 0 to MBR register

X←2001; Assume X to be an address location 2001

READ X; Read a value from memory location 2001 into AC

BRZ 1007; Branch to location 1007 if AC is zero (Conditional branch on zero)

ADD MBR; add the content of MBR to AC and store result to AC

TRAS MBR; Transfer the contents of AC to MBR 

INC X; Increment X to point to next location 

JUMP 1001;Loop back for further processing.


Related Discussions:- Describe program control instructions

Explain pre-emptive scheduling, Explain Pre-emptive scheduling? Pre-em...

Explain Pre-emptive scheduling? Pre-emptive scheduling: in its approach, center processing unit can be taken away from a process if there is a require while in a non-pre-empt

Explain anonymous FTP, Explain Anonymous FTP. Use of a login password...

Explain Anonymous FTP. Use of a login password and name helps maintain file secure from unauthorized access. Though, sometimes these authorizations can also be inconvenient.

Senior project, any ideas about senior project topic

any ideas about senior project topic

What is wireless transmission systems, What are wired and wireless transmis...

What are wired and wireless transmission systems? Transmission Systems: Modern type long distance transmission systems can be placed in three wide categories: 1. Radio Sy

Explain how server form post-back works, Briefly explain how server form po...

Briefly explain how server form post-back works?  Post Back: The process in which a Web page sends data back to the similar page on the server. View State: View State is the m

Explain in detail about the random scan display, Explain in detail about th...

Explain in detail about the Random Scan Display   This device using CRT directs the electron beam only to the parts of the screen where a picture is to be drawn. This kind of d

System software, define the properties of interactive operating systems

define the properties of interactive operating systems

Write the html code to web page to insert an image, Write the HTML code to ...

Write the HTML code to accomplish the web page to insert an image onto a page using good.gif as image and having "welcome" as the ALT text. The HTML code to accomplish the web

Data structures.., in asingle function declaration what is maximum no of st...

in asingle function declaration what is maximum no of statements that may be recursive calls

Find the physical address of instruction, Q. Find the Physical address of i...

Q. Find the Physical address of instruction? Value of Instruction Pointer and holding address of instruction = 1234h Value of code segment register (CS) = 448Ah Physical

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