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 various applications of shift register, Lists out some applications ...

Lists out some applications of Shift Register. Ans: Applications of Shift Registers: a. Serial to Parallel Converter b. Parallel to Serial Converter c. Delay li

What are the two ways in which the system using cache, What are the two way...

What are the two ways in which the system using cache can proceed for a write operation? Write by protocol technique Write-back or Copy-back protocol method

Define dynamic loading, Define dynamic loading. To get better memory-sp...

Define dynamic loading. To get better memory-space utilization dynamic loading is used. With dynamic loading, a routine is not loaded unless it is called. All routines are kept

Computer Architecture, can u please tell me the assembly language program f...

can u please tell me the assembly language program for carry look ahead adder that can run in 8086 emulator?? its urgent

Define compilers and interpreters with high level language, Define compiler...

Define compilers and interpreters with high level language? Both compilers and interpreters are available for most high-level languages. Though LISP and BASIC are in particular

Fuzzy logic - artificial intelligence, Fuzzy set theory provides a means fo...

Fuzzy set theory provides a means for modeling the kind of uncertainty associated with vagueness, with imprecision, and/or with a lack of information regarding a particular element

What is literal, Meaning of Literal is:- Literal is string constant.

Meaning of Literal is:- Literal is string constant.

What are the ways to create a new form, What are the ways to create a new f...

What are the ways to create a new form? You can make a new form in any of the following three ways: Using AutoForm: You can make a form based on a single table or query qui

Importance of barrier free design and web accessibility, Problem: (a) ...

Problem: (a) Accessibility can be classified as below: (i) Barrier-free design (ii) Web accessibility. Describe the importance of barrier free design and web accessibi

Translate the sentences into predicate calculus, Translate each of the foll...

Translate each of the following sentences into predicate calculus, conceptual dependencies, and conceptual graphs: 1. Bill sold the book to the book store." 2. "John borrowed

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