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 is memory interleaving, Q. What is Memory Interleaving? In this sc...

Q. What is Memory Interleaving? In this scheme main memory is splitted in 'n' equal-size modules and CPU has separate Memory Base register and Memory Address Register for every

What is big endian and little endian format, What is big endian and little ...

What is big endian and little endian format? The name big endian is used when lower byte addresses are used for the more important of the word. The name little endian is used f

Explain time division switching, Explain Time Division Switching. Ti...

Explain Time Division Switching. Time Division Switching: A switching component can be shared at the same time with number of active speech circuits. It is the principle of

Write an algorithm for the braking system, Question: a) Consider a car ...

Question: a) Consider a car having a collision detection mechanism. Write an algorithm (in simple English) to illustrate the collision detection mechanism. b) The same car

Requirements of decision support system, Q. Requirements of decision suppor...

Q. Requirements of decision support system? a) Fast computation A decision maker is able to perform a large number of computations very quickly and that too at a low cost

What is an interpreted languages, What is an interpreted languages In ...

What is an interpreted languages In interpreted languages, the instructions are implemented immediately after parsing. Both tasks are done by the interpreter. The code is sav

Why is packet switching important, Why is packet switching important? Give ...

Why is packet switching important? Give at least two reasons. Packet switching is significant due to the following two purposes: 1. A sender and the receiver require coordin

Computer graphics, raster scan and random display technology

raster scan and random display technology

Will case infer priority register if yes how give an example, Will case inf...

Will case infer priority register if yes how give an example? Yes case can infer priority register depending on coding style reg r; // Priority encoded mux, always @

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