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

Execution of a machine instruction, Execution of a machine instruction: ...

Execution of a machine instruction: Execution of a machine instruction on modern processors involves a complex sequence of operations with multiple cycles. One instruction cyc

Project, Identify three factors to consider in determining the competitive ...

Identify three factors to consider in determining the competitive value of information technology. Justify the selected factors. Of the factors selected, determine if each fact

Reflex agent-artificial intelligence, Reflex agent-Artificial Intelligence ...

Reflex agent-Artificial Intelligence If an agent decides and executes an action in response to a sensor input without consultation of its world, then it may be considered a ref

Classification of computers, Classify computer systems according to capacit...

Classify computer systems according to capacity. How they are different from computers according to the classification of technology. Provide comparative

Network engenering, What role would you assign to each of the four workstat...

What role would you assign to each of the four workstation and any other equipment

Describe the binary search algorithm, QUESTION 1 Describe the binary se...

QUESTION 1 Describe the binary search algorithm using an example of your own. QUESTION 2 (a) By showing all your workings, give a big-O estimate for f(x) = (x + 1)lo

Bus structure, which computer architecture use single bus structure??????? ...

which computer architecture use single bus structure??????? tells the name and little bit working

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