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

Write short notes on joint fiction reserve, QUESTION (i) Write short no...

QUESTION (i) Write short notes on each of the following: a) Shelf reading b) Joint Fiction Reserve c) London and South-Eastern Library Region d) Document access

Instruction pipeline, How branching takes place in Instruction pipeline. Ex...

How branching takes place in Instruction pipeline. Explain with suitable examples.

Data type, Data Type:  Data Type: Anything that is processed by a comp...

Data Type:  Data Type: Anything that is processed by a computer is called data. There are different types of data that can be given to the computer for processing. A  data typ

Display the item in red colour on a web page, QUESTION (a) Give the app...

QUESTION (a) Give the appropriate syntax to implement a Client-Side Image Map, specifying all possible attributes where required (b) List the benefits of using Cascading Sty

Concept of operating system, Concept of operating system: An operating...

Concept of operating system: An operating system is an essential software component of a computer system. The basic  objectives of an operating system are to make the computer

Comp 100, I have an account in my www.itlab.com and i have a test and it s...

I have an account in my www.itlab.com and i have a test and it should do tonight, so do you have any one to help me and do this test and it is about excel

Diskless workstations, Diskless workstations:    Most people assume th...

Diskless workstations:    Most people assume that the operating system is stored on a disk that is connected directly to the computer, but this is not necessarily true. If the

Define server clustering, Question 1 Discuss the impacts of disaster faced...

Question 1 Discuss the impacts of disaster faced by the organization Question 2 Explains the steps involved in disaster recovery planning Question 3 What do you mean by

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