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

Why is TCP called end-to-end protocol, Why is TCP called end-to-end protoco...

Why is TCP called end-to-end protocol? TCP is termed as an end-to-end protocol as this provides a connection directly by an application in one computer to an application on a r

Explain about the prepurchase interaction activity, Explain about the Prepu...

Explain about the Prepurchase Interaction activity. Prepurchase Interaction: This interaction for consumers comprises three activities: • Product or service search and di

Layout for the assumed penalty, Solve the following 8-department problem us...

Solve the following 8-department problem using the MIP method.  What is the resulting layout and flow-distance score?  Note that the aspect ratio of each department should be 2.

Explain the logic symbols - flip flops, Explain the Logic symbols - Flip Fl...

Explain the Logic symbols - Flip Flops? These flip-flops are as well called Master-Slave flip-flops simply because their internal construction is divided into two sections. Th

Define miss rate, Define miss rate? It is the number of misses' states ...

Define miss rate? It is the number of misses' states as a fraction of attempted accesses.

What are the digital certificates of hardware computations, What are the Di...

What are the Digital certificates of hardware computations Digital certificates are highly dependent on hardware computations, it is essential that mechanisms are evolved to i

Determine the handles data rate of broad band isdn, Broad Band ISDN handles...

Broad Band ISDN handles data rate of about (A) 64 kbps                                      (B) 100 mbps (C) 5.4 mbps                                    (D) 2.048 mbps

Explain isdn addressing with a example, Explain ISDN Addressing with a exam...

Explain ISDN Addressing with a example. A sub address, though a part of the ISDN address, is not seems as an integral part of the numbering scheme. Sub-address is carried in a

Conclusion - artificial intelligence , Conclusion - artificial intelligence...

Conclusion - artificial intelligence : If we can determine what the exactly state of the world will be after an agent's action, so we can say the environment is deterministic.

Name the modes of 8255 programmable peripheral interface, What are the diff...

What are the different modes in that 8255 Programmable Peripheral Interface (PPI) can operate?  24 I/O lines in 3-8-bit port groups - A, B, C A, B can be 8-bit input

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