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

Name two special purpose registers, Name two special purpose registers. ...

Name two special purpose registers. Index register Stack pointer

Define program counter, Define Program Counter(PC) The Program Counter ...

Define Program Counter(PC) The Program Counter holds the address of the next instruction to be read from memory after the current instruction is implemented.

i open an ms access database, How can I open an MS Access database that ha...

How can I open an MS Access database that has been converted to a current version? Ans) MS Access is not backwards compatible. A workaround to share tables among different versi

What are the main features of uml, What are the main features of UML ...

What are the main features of UML Defined system structure for the object modelling Support for all different model organization Strong modelling for behaviour an

Advntages of parallel processing oversequential computation, Advntages of p...

Advntages of parallel processing oversequential computation Parallel computing has the following benefits over sequential computing: i)    Accumulate time ii)   Solves b

Development of a successful system, The success of a system relies on the a...

The success of a system relies on the approach of building it. If development approach is right then system will work successfully. Figure below portrays a System Development Life

Explain working of supercomputer, Q. Explain working of Supercomputer? ...

Q. Explain working of Supercomputer? Supercomputers, capable of executing in excess of one billion floating-point operations per second (FLOPS), are very powerful, extremely hi

What is strong-typing versus weak-typing, What is strong-typing versus weak...

What is strong-typing versus weak-typing? Which is preferred? Why? Strong type is checking the types of variables as early as possible, usually at compile time. Whereas weak ty

Create new user account - system administrator, A common task for a system ...

A common task for a system administrator is to create new user accounts. In this lab you will be creating output that looks like an /etc/passwd file. The Problem You are to

Explain multiple instruction and single data stream (misd), Multiple Instru...

Multiple Instruction and Single Data stream (MISD): In this type of organization multiple processing elements are ordered under the control of multiple control units. Every contro

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