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

Define multi programming, Define multi programming? Many operating syst...

Define multi programming? Many operating systems are designed to enable the cpu to process a number of independent programs concurrently. This concept is  known as multi progra

Efficiency - metrics for performance evaluation, Q. Efficiency - Metrics fo...

Q. Efficiency - Metrics for performance evaluation? The other significant metric employed for performance measurement is efficiency of parallel computer system it implies that

Define software is in machine language or not, Define Software is in machin...

Define Software is in machine language or not Software is in machine language, today it is often developed by first writing in a high-level language or an assembly language or

Explain about the logical devices, Explain about the Logical Devices ...

Explain about the Logical Devices Locator, to indicate a position and/or orientation Pick, to select a displayed entity To input a single value in the space of re

Differentiate memory mapped and isolated i/o, Q. Explain how does CPU perf...

Q. Explain how does CPU perform Read and Write operation on peripheral device taking suitable example in case of Asynchronous Technique. Differentiate Memory mapped and Isolated

What is reentrant tasks and functions, What is reentrant tasks and function...

What is reentrant tasks and functions Tasks and functions without optional keyword automatic are static , with all declared items being statically allocated. These items will b

Explain about shared features of olap, Shared executes most of the security...

Shared executes most of the security features into OLAP. If multiple accesses are needed admin can make essential changes. The default security level for all OLAP products is read

How do you get workflow automation in e-business environment, How do you ge...

How do you get workflow automation into e-business environment? In order to run smoothly, organizations frequently standardize processes across the organization and support use

C programming, write a program to find the area under the curve y=f(x) betw...

write a program to find the area under the curve y=f(x) between x=a and x=b,integrate y=f(x) between the limits a and b

Proof by contradiction - artificial intelligence, Proof by Contradiction - ...

Proof by Contradiction - Artificial intelligence So, both backward chaining andforward chaining have drawbacks. Another approach is to think regarding proving theorems by contr

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