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

Omputer applications 2, true or false-- most designs of a desktop publishin...

true or false-- most designs of a desktop publishing document needs to follow clear, specific rules pertaining to design

Assignment, write an essay explaining the following: 1.Storage aspects a. D...

write an essay explaining the following: 1.Storage aspects a. Disk formatting, b.Disk boot block ,c.Bad block removal, d.Compensation.

Explain se process model objective, Question 1 Explain attributes, propert...

Question 1 Explain attributes, properties, and characteristics of system Question 2 What do understand from Organizational Aspects of System Life Cycles? Explain Question

ALP Program to find 10''s complement, I would like to know how to write a p...

I would like to know how to write a program for a 8086 microprocessor in ALP to find 10''s complement of a packed BCD number.

Discuss the attributes of speech codec, Question 1 What is mobile telephon...

Question 1 What is mobile telephone initialization? Explain the three main goals of this procedure Define GSM system operations Introduction to mobile telephone initializ

Function, function of arithmetic logic unit

function of arithmetic logic unit

Indexing and abstracting databases, Indexing and Abstracting Databases: ...

Indexing and Abstracting Databases: A study of growth of indexing and abstracting services over the years would show that during the past two centuries, these services have be

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