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

Design a half adder, Q. Design a half adder? In half adder inputs are: ...

Q. Design a half adder? In half adder inputs are: The augend let's say 'x' and addend 'y' bits. The outputs are sum 'S' and carry 'C' bits. Logical relationship betwee

How exceptions are handled in java, How exceptions are handled in java? ...

How exceptions are handled in java? Exception handing In Java: A java exception is an object which describes an exceptional condition which has occurred in a piece of code.

C program, a c program to implement multiple stack in a single array

a c program to implement multiple stack in a single array

Differentiate memory mapped and isolated i/o, Q. Explain how does CPU perf...

Q. Explain how does CPU perform Read and Write operation on peripheral device taking suitable example in case of Asynchronous Technique. Differentiate Memory mapped and Isolated

Explain the main tags of wireless markup language, Discuss the main tags of...

Discuss the main tags of WML. Tag Definition of Wireless Markup Language: This defines the starting and the ending of the page, as .   this explains

What are vectored interrupts, What are vectored interrupts? To decrease...

What are vectored interrupts? To decrease the time involved in the polling process, a device requesting an interrupt may recognize itself directly to the processor. Then the pr

Relationship between distributed and mobile computing, a) Briefly describe...

a) Briefly describe the relationship between distributed computing, mobile computing and pervasive computing. b) Suppose the following scenario, which demonstrate the possibili

Dbms, what is cascading rolback?

what is cascading rolback?

Convert integer into numerical equivalents, Convert the following integers ...

Convert the following integers into their numerical equivalents in the indicated bases. Be sure to use the correct number of significant figures for each case and show how the corr

Why echo suppressor is detrimental to full duplex operation, Echo suppresso...

Echo suppressor is detrimental to full duplex operation because? This disables one of the two pairs in a four-wire trunk line while a signal is detected upon another pair.

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