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

Explain asymmetric cryptographyand its components, Explain Asymmetric crypt...

Explain Asymmetric cryptographyand its components. Asymmetric or public-key cryptography be different from conventional cryptography in which key material is bound to a single

Define processor clock, Define processor clock. Processor clock is expl...

Define processor clock. Processor clock is explained as the time periods in which all operations and data transfer within the processor take place.

State in brief about the pseudo instruction, State in brief about the pseud...

State in brief about the pseudo instruction A pseudo instruction isn't a real instruction. CPU can't execute it. It often requires a complex architectural operation and if it w

Explain about the term middleware, Explain about the term Middleware. M...

Explain about the term Middleware. Middleware is the term frequently used to explain the application or business logic present within an application server. Unfortunately, simi

Describe the concepts of information systems delivery cycle, Write a 2-3 pa...

Write a 2-3 page paper (excluding title, abstract, introduction, and references) describing the concepts of the Information Systems Delivery Cycle (SDLC) and how the Project Manage

What is the length of function code at user-command, What is the length of ...

What is the length of function code at user-command? Every menu function, push button, or function key has an associated function code of length FOUR (for example, FREE), which

Operating system.., what is network operating system design issues

what is network operating system design issues

Functions employed for messaging passing, Q. Functions employed for messagi...

Q. Functions employed for messaging passing? The functions employed for messaging passing are: int MPI_Send(void *msgaddr, int count, MPI_Datatype datatype, int dest, int ta

Secondary storage - computer architecture, Secondary storage: Secondar...

Secondary storage: Secondary storage (or external memory) differs from primary storage in that aspect it is not accessible by the CPU directly. The computer typically uses its

Explain interactive reporting, What is interactive reporting? A classic...

What is interactive reporting? A classical non-interactive report having of one program that makes a single list.  Instead of one extensive and detailed list, with interactive

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