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

Management information system, suggest 5 ways by which new products and ser...

suggest 5 ways by which new products and services can be developed using management information system

Pipelining, tellme the types of pipelining

tellme the types of pipelining

Threading Module of python, The latest threading module comprised with Pyth...

The latest threading module comprised with Python 2.4 provides much more powerful, high-level hold for threads than the old thread module. The threading module depictions all the m

Circuit switching and , Circuit Switching: Many switching techniques a...

Circuit Switching: Many switching techniques are in use. One of them is line or circuit switching in which a communications path is actually established before the message is

Homework , Using only the digits 1-6 how many five digit numbers can be for...

Using only the digits 1-6 how many five digit numbers can be formed? How many of these have at least a 5? How many of them have either no 5 or no 6?

Software engineering, how will a poorly conducted feasibility study affect ...

how will a poorly conducted feasibility study affect an implemented system

Computer input, COMPUTER INPUT: Figure shows input information for a ty...

COMPUTER INPUT: Figure shows input information for a typical airborne digital computer.  The sensors in Figure develop analogue electrical signals representing: -

#title., what is input and output device? explain meaning of input and outp...

what is input and output device? explain meaning of input and output devices

Algorithms and flowcharts, 1. Write an algorithm and draw a flowchart to ac...

1. Write an algorithm and draw a flowchart to accept the names and gross salary of 5000 employees and to generate the net pay. If the gross salary is greater than N 50,000 declare

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