What help with this Assembly language Subroutine, Basic Computer Science

Assignment Help:
Write an ARM subroutine which will extract a substring from a string. You will need to use the library routine malloc to allocate memory for the new string.

The subroutine signature is:
char * mysubstring( char string[], int start, int end ) ;

where char string[] is the string to extract the substring from; it is passed into the ARM routine as a pointer in a1 to the first element of the character (byte) array,
int start is the first character to extract from the string to the substring; it is passed into the ARM routine as a value in a2,
int end is the last character to extract from the string to the substring; it is passed into the ARM routine as a value in a3.
The return is a pointer to the new string.

#include
#include

extern char * mysubstring( char string[], int start, int end ) ;

int main( int argc, char * argv[] )
{
char tosub[] = "this is the string to substring" ;
char * result ; /* pointer to new string */

result = mysubstring( tosub, 12, 17 ) ;
printf( "String: %s\nSubstring: %s\n", tosub, result ) ;

exit( 0 ) ;

}

To use the library routine malloc you need to calculate the number of bytes of memory you are requesting, put that number in a1 and bl malloc. Upon return from the library routine a1 will have a pointer to the allocated memory.

You may assume that the start and end values are within the string and malloc returns a proper pointer value.

Related Discussions:- What help with this Assembly language Subroutine

College management system project, E-R diagram and details for college mana...

E-R diagram and details for college management system

Flowchart, create a flowchart showing average score for the 3 quizzes assum...

create a flowchart showing average score for the 3 quizzes assume that there are 3 sections each having 5 students the only valid number to be entered is 1-100 for the quizzes shou

Algorithmic, define it #Minimum 100 words accepted#

define it #Minimum 100 words accepted#

Computers in laboratory organisation and management, Computers can be used ...

Computers can be used for better and more efficient management and organisation of laboratories. A computer like the human brain receives information, stores and processes it and t

Discuss the roles of system analysts in detail, Question 1 Explain the ...

Question 1 Explain the following system design tools in detail System Flowcharts Decision tables Decision trees Organization charts Question 2 Write s

Software engineering, how will a poorly conducted feasibility study affect ...

how will a poorly conducted feasibility study affect an implemented system

Word processing software, Word Processing Software : The main use for word...

Word Processing Software : The main use for word processing is found in secretarial offices and small publishing companies. However, if you are involved in generating your own cor

Definition of Internal hardware interruptions, Internal interruptions are...

Internal interruptions are produced by convinced events which come during the execution of a program. These types of interruptions are handled on their totality by the hardware and

Variables and constants, Variables and Constants: These are the smalle...

Variables and Constants: These are the smallest components of a programming language.  For writing a program, one must know how to use the internal memory of a computer. A Com

Describe counting instructions, They are used to reduce or enlarge the cont...

They are used to reduce or enlarge the content of the counters. DEC INC DEC INSTRUCTION Idea: To diminish the operator. Syntax: DEC destiny This action subtracts 1 from the destiny

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