Write this ARM assemble language program, Basic Computer Science

Assignment Help:
Programming Assignment
CS252 Spring 2014

Write an ARM assembly language subroutine that performs according to the following specification (Caesar cypher).

Given a mixed case alphabetic string from the C driver program, convert it to all upper case and create a new string for return to the C program. The new string has the characters from the old string replaced by upper case characters from the alphabet offset by the given amount in the alphabet.

If the character string is ‘Abc’ with an offset of -3 the new string would be ‘XYZ’. For characters in the alphabet such as ‘mno’, the alphabet is ‘JKL’. The beginning of the alphabet is wrapped to the end.

To convert a character to upper case, AND the character with 0xDF. Do not process the space character (leave it as a space) or the NULL byte terminator but be sure to include the NULL byte in the new string.

The C driver code:
/* C code for cipher */
#include
#include

extern char * cypher( char * s, int offset ) ;

int main( int argc, char * argv[] )
{
?char string[] = "The quick brown fox jumped over the lazy dog" ;
?char * result ;
?int offset = -5 ;

?result = cypher( string, offset ) ;
?printf( "Original:%s\n", string ) ;
?printf( "Coded: %s\n", result ) ;
?
?exit( 0 ) ;
}

The assembly routines definition is:
?extern char * cypher( char * s, int offset )
?where?char * s is the pointer to the string,
?int offset is the integer distance to move
?returns a pointer to a string.

To determine the length of the string in order to reserve space for the new string use the library routine strlen. Register a1 contains a pointer to the string to measure and on return register a1 has the number of characters in the string. You need to add one to this result since strlen does not account for the null byte at the end.
You can pass this length to the malloc library routine to obtain space for the new string.

Related Discussions:- Write this ARM assemble language program

Inside earth, What are two types of evidence geologists use to learn about ...

What are two types of evidence geologists use to learn about Earth''s interior.?

What is the use of system bus ?, The system bus is a cable which carries da...

The system bus is a cable which carries data communication among the major components of the computer, as well as the microprocessor. Not all of the communication that uses the bus

Finite Automata, (S**)*=S*** is this set bigger than S*??

(S**)*=S*** is this set bigger than S*??

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

Mr, Please what is the different between computer science and information t...

Please what is the different between computer science and information technology? Which of this require too much reading? Thanks

Analogue to digital converter, Analogue to digital converter: In an ADC...

Analogue to digital converter: In an ADC a range of input values must correspond to a unique digital word.  The type of code used depends on the system but here only binary cod

History , when was the first computer made

when was the first computer made

Primary or foreign key, QUESTION Your Library is currently offering acc...

QUESTION Your Library is currently offering access to the Internet for its subscribers on a fee paying basis. Subscribers should make a booking for each slot of one hour in adv

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