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

Explain FDM : Frequency Division Multiplexing, Frequency Division Multiplex...

Frequency Division Multiplexing : FDM is an analog technique that is applied when he bandwidth of link is greater than the combined bandwidth of the signals to be transmitted. a

Algorithms and pseudocodes.., how do you write the algorithm and the pseudo...

how do you write the algorithm and the pseudo code for cramer''s rule in visual basic.

OPERATING SYSTEM, WHAT IS MULTIPLE CONTIGUOUS VARIABLE PARTITIONING

WHAT IS MULTIPLE CONTIGUOUS VARIABLE PARTITIONING

Explain the operations of alu, Question 1 Explain the operations of ALU ...

Question 1 Explain the operations of ALU Question 2 Write down the Booth's Multiplication Algorithm with an example Question 3 Explain the characteristics of memor

What are search engines, QUESTION 1 What are search engines? QUESTI...

QUESTION 1 What are search engines? QUESTION 2 Write short notes on the inverted file. QUESTION 3 Write short notes on: (i) Derivative indexing (also known a

Optical disk storage and cd - rom, Optical disk storage and cd - ROM: ...

Optical disk storage and cd - ROM: Optical disk storage is relatively new alternative to magnetic storage. Digital data is burnt into the surface of a plastic disk coated with

Networking.., write advantages and disadvantages of private and public netw...

write advantages and disadvantages of private and public network

List the various applications of ai, Question 1 What are the important Iss...

Question 1 What are the important Issues in Search Problem Question 2 What do you mean by Predicates? Briefly explain Question 3 What are the advantages of Wireles

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