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

Differences between batch systems versus real-time systems, Question 1: ...

Question 1: a. Give NINE general properties of an MIS b. Name and explain the THREE main Problems and Issues of EIS Question 2: a. What are information systems for?

Why is c standard library needed, Why is C standard library needed?  C ...

Why is C standard library needed?  C Standard Library: C would have been a tough programming language in absence of the standard library. The standard library in C contains

Versions of small computer systems interface, Q. Versions of small computer...

Q. Versions of small computer systems interface? SCSI-1 calls for a cable with 8 data wires plus one for parity. SCSI-2 allows use of multiple cables to support 16- or

Explain the use of ssl to secure the network, Explain the use of SSL to sec...

Explain the use of SSL to secure the network.  SSL (Secure Sockets Layer) is a protocol developed by Netscape for transferring private documents by the Internet. SSL works by u

Explain the outsourcing barriers that an organization faces, Explain the ou...

Explain the outsourcing barriers that an organization faces. 1. Critical operations that cannot be outsourced. 2. Negative customer reaction. 3. Employee resistance. 4

Basic characteristics of an experts system, An experts systems must perform...

An experts systems must perform well that is achieve the same levels of performance in the domain of interest that human experts can achieve. But simply producing good so

State and prove demorgan’s first theorems, State and prove Demorgan’s First...

State and prove Demorgan’s First theorems: Ans. Statement of First Theorem of De Morgan: = A‾. B‾   Proof: The two sides of the equation i.e. = is represented with logic

What is read only memory, Read only memory (ROM) ROM holds the instruct...

Read only memory (ROM) ROM holds the instructions for starting up the computer. This sort of memory can only be read and can't be altered (that implies deleted or written to) a

What are the logic micro-operations, Q. What are the Logic Micro-operations...

Q. What are the Logic Micro-operations? Logic operations are fundamentally binary operations that are performed on string of bits stored in the registers. For a logic micro-ope

Program in java, Write a program to display grade message according to the ...

Write a program to display grade message according to the marks

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