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

What are kinds of processors, Processors can broadly be seperated into the ...

Processors can broadly be seperated into the categories of: CISC, RISC, hybrid, and special purpose.

Explain about the term intranet in brief, Explain about the term Intranet i...

Explain about the term Intranet in brief. Intranet: An Intranet is a form of information system which facilitates communication into the organizations in between widely

Paging, specification of paging ram size is 12 frames

specification of paging ram size is 12 frames

What property of the architecture of 3g networks, Question: (a) Explain...

Question: (a) Explain how a Mobile Terminating call, from a PSTN phone, is processed in a GSM network. Illustrate your answer with a diagram. (b) Top-Net, a new telecommuni

Single program multiple data, SPMD is actually a "high level" programming m...

SPMD is actually a "high level" programming model that can be built upon any combination of the previously mentioned parallel programming models. A single program is executed by al

Write a short note on pointer declaration, Write a short note on pointer de...

Write a short note on pointer declaration A simple variable in a program is stored in a certain number of bytes at a particular memory location, or address, in the machine. Poi

What is parsing in grammatical structure, What is Parsing? Parsing: ...

What is Parsing? Parsing: It is the process of analyzing a text, made of an order of tokens, to find out its grammatical structure regarding a given formal grammar. Parsing

Phython, super ascii string checker

super ascii string checker

Explain about magnetic tape, Explain about Magnetic tape      a) They a...

Explain about Magnetic tape      a) They are mostly used for keeping files of data  b )It is one of the cheapest and slowest methods for storage

Determine less propagation delay in synchronous-ripple ckt, You have two co...

You have two counters counting up to 16, built through negedge DFF, First circuit is synchronous and second is "ripple" as cascading, which circuit has a less propagation delay? Wh

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