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

Control hazard and delayed branching, Described Instruction or control haza...

Described Instruction or control hazard? Ans: The pipeline can be stalled due to delay in the availability of an instruction. For instance, this may be a result of a miss in t

What is a pipeline hazard, What is a pipeline hazard? Any condition tha...

What is a pipeline hazard? Any condition that causes the pipeline to stall is known as hazard. They are also known as stalls or bubbles.

Write short note on associated vs. common channel signaling, Write short no...

Write short note on Associated vs. Common channel signaling. Associated vs Common channel signalling: The out band signalling suffers from the very restricted bandwidth.

Find the nyquist rate, Find the Nyquist rate for the following signals: (a)...

Find the Nyquist rate for the following signals: (a) x(t) = 5 sin 3000πt cos 4000πt (b) A binary channel with bit rate 36000 bps is available for PCM voice transmission. Fi

What is zero address instruction, Zero address instruction.  It is also...

Zero address instruction.  It is also possible to use instruction where the location s of all operand is explained implicitly. This operand of the use of the method for storing

Speed up - metrics for performance evaluation, Q. Speed Up - metrics for pe...

Q. Speed Up - metrics for performance evaluation? Speed up is ratio of time needed to execute a given program employing a specific algorithm on a machine with single processor

Human intelligence in culture - artificial intelligence, Human intelligence...

Human intelligence in culture: Understand human intelligence in culture  "AI" can be seen as just the latest tool in the philosopher's toolbox for answering questions about

Quick sort exhibit its worst-case behaviour, In which input data does the a...

In which input data does the algorithm quick sort exhibit its worst-case Behaviour? The Quick Sort method exhibits its worst-case behavior when the input data is " Already Comp

Give difference between assembler and compiler, Give difference between ass...

Give difference between assembler and compiler. Assembler: It is the translator for an assembly language of computer. An assembly language is a low-level programming language

What is the analysis techniques object modelling, What is the Analysis Tech...

What is the Analysis Techniques Object Modelling Object modelling is very significant for any object oriented development, object modelling shows static data structure of real

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