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

Software, Software: A computer system consists of two parts - hardware...

Software: A computer system consists of two parts - hardware and software. The first part, computer hardware, refers to all the visible components of the computer system:  key

Describe CPU registers , The CPU has four internal registers, each of 16 bi...

The CPU has four internal registers, each of 16 bits. The first four, AX, BX, CX, and DX are common use registers and can also be used as 8 bit registers, if used in such a way it

Oop, evolution of oop

evolution of oop

Algorithm - programming language, Algorithm : Once a problem has been defi...

Algorithm : Once a problem has been defined precisely, a procedure or process must be designed to produce the required output from the given input. Since a computer is a machine t

Compare between file processing system and dbms, Problem a. Compare bet...

Problem a. Compare between file processing system and DBMS >>This is a comparison of DBMS with file processing system which the answer has to be searched from the GOOGLE an

Object oriented programming, Write a method called Grade that takes a numer...

Write a method called Grade that takes a numeric score and returns a letter grade. Use the rule that 90 to100 is an A, 80 to 89 a B, 60 to 79 is a C, 45 to 59 is a D, and less th

Courier company , disvange and advantege of providing intternet sservice to...

disvange and advantege of providing intternet sservice to customer

As, access,excel and ms word/

access,excel and ms word/

Pseudocode, How Much Insurance? Many financial experts advise that property...

How Much Insurance? Many financial experts advise that property owners should insure their homes or buildings for at least 80 percent of the amount it would cost to replace the st

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