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 Video Card Interfaces, Q. What is Video Card Interfaces? A video i...

Q. What is Video Card Interfaces? A video interface is the link of video system to rest of the PC. To improve video performance there is required to be an intimate connection betw

Explain about the acoustic tablet, Explain about the Acoustic tablet Ac...

Explain about the Acoustic tablet Acoustic (or sonic) tablet use sound waves to detect a stylus position. Either strip microphones or point microphones can be used to detect th

increase the number of rows or columns in a worksheet, How can I increase ...

How can I increase the number of rows or columns in a worksheet? Ans) In Excel, each workbook has 255 columns and 65,526 rows. These values are fixed and cannot be changed. If

Convert the following binary numbers into octal, Q. Convert the following B...

Q. Convert the following BINARY numbers into OCTAL, double check by converting the result OCTAL to BINARY. a) 111.111 b) 10110111 c) 0.11111

What are the attributes of the method, What are the attributes of the metho...

What are the attributes of the method? During implementation a process is characterized by various attributes maintain by the system: Its state Its identification

How to create a bugzilla account? , 1. Enter your "E-mail address...

1. Enter your "E-mail address" and "Real Name" (or whatever name you need to call yourself) in the spaces given, then select the "Create Account" button. 2. Within moments, you

Inverse of exclusive or known as xnor gate, Truth table of NAND and NOR can...

Truth table of NAND and NOR can be made from NOT (A AND B) and NOT (A OR B) correspondingly. Exclusive OR (XOR) is a special gate whose output is one only if two inputs aren't equa

Smart card & e-cash, Smart Card & E-Cash E-cash storable smart cards ca...

Smart Card & E-Cash E-cash storable smart cards can kept and dispense cash electronically, making bills and coins lesser essential. It transfers funds over phone lines, making

Describe about the embedded applications assembly, Describe about the Embed...

Describe about the Embedded applications assembly Embedded applications assembly and C programs are developed since embedded programs aren't large. For all others high-level an

Determine the level of state decomposition, Determine the level of state de...

Determine the level of state decomposition The level of state decomposition must be determined by judgement. A too fine grained model is unsuitable, such as, modelling all poss

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