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

Explain the raster scan display system, Question 1 Explain boundary fill a...

Question 1 Explain boundary fill and flood fill polygon filling algorithm Question 2 Draw and explain the block diagram of typical workstation Question 3 Explain the ras

Printers, Printers: Printers: Printers exist in a variety of forms:  ...

Printers: Printers: Printers exist in a variety of forms:  Line Printers: These have been widely used for many years in large computer installations. They are design

Apple''s rbv, What''s a resource based view of Apple Corporation?

What''s a resource based view of Apple Corporation?

Create a queue, QUESTION (a) Give the representation of a queue as an a...

QUESTION (a) Give the representation of a queue as an abstract data type. (b) What is a priority queue? Give two types of priority queues. (c) The following program does

Python Strings and Python Lists, Python Strings: Strings in Python are rec...

Python Strings: Strings in Python are recognized as an adjacent set of characters in among quotation marks. Python permits for either pairs of single or double quotes. Subsets of s

Extension.., short note about extension..

short note about extension..

Algorithm, solve three given number in ascending order through algorithm

solve three given number in ascending order through algorithm

Rom, what is rom

what is rom

M s word., explain the steps to form a colourful card

explain the steps to form a colourful card

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