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

Internetworking, You have been approached by Company XYZ to design and depl...

You have been approached by Company XYZ to design and deploy a new network that will span three cities in Queensland: Brisbane (12 users), Gold Coast (8 users), and Cairns (6 users

Java, what is meant by deliverable in strus base applications

what is meant by deliverable in strus base applications

Compact diskette (cd), Compact Diskette (CD) CD-ROM ...

Compact Diskette (CD) CD-ROM CD-ROM stands for Compact Disk-Read Only Memory. This disk comes with data already stored in it. It can store around 640 MB of

Spreadsheet software , Spreadsheet Software : Consider the grid in Fig. ...

Spreadsheet Software : Consider the grid in Fig. 9.4. It is split into rows and columns and is a pictorial representation of a typical spreadsheet program.  Figure: Spr

Data transmission, #quesetion..explain the concept of data transmission giv...

#quesetion..explain the concept of data transmission giving details of the transmission rate and bandwidth with details explanation of the transmission media

Operating system, Ask question describes deadlock avoidance#Minimum 100 wor...

Ask question describes deadlock avoidance#Minimum 100 words accepted#

Project, My son has a project assignment he has problem with. The only thin...

My son has a project assignment he has problem with. The only thing is, it is due in 20 mins. can someone be able to help him? if so, how much is the fee?

Global positioning system, How does GPS work in the field of Sport or athle...

How does GPS work in the field of Sport or athletics?

Networks, Networks: There are different interpretations for the term °...

Networks: There are different interpretations for the term °nets% The Oxford English Dictionary states that 'a network is an interconnected chain or system of immaterial thing

Surveying, describe the two fundament purpose of surveying

describe the two fundament purpose of surveying

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