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

Types of operating systems, Operating Systems:  An operating system is a se...

Operating Systems:  An operating system is a set of programs that manage computer hardware resources and provide common services for application software.  There are following kind

Library function, Library function :   These are the functions supplied...

Library function :   These are the functions supplied with the programming language. The code or definition of library functions does not have to be written in a user program w

Explain FDM : Frequency Division Multiplexing, Frequency Division Multiplex...

Frequency Division Multiplexing : FDM is an analog technique that is applied when he bandwidth of link is greater than the combined bandwidth of the signals to be transmitted. a

Describe the protocol used by the mmu, Question 1: a) A distinction is...

Question 1: a) A distinction is often made between computer architecture and computer organisation. Describe, using examples, the meaning of computer architecture. b) Name

Programming Project 1, Programming Project You will implement 2 algorithms...

Programming Project You will implement 2 algorithms to solve the single source shortest paths problem, Bellman-Ford Algorithm and Dijkstra''s algorithm Allowed programming languag

Perverse software, Perverse software: Perverse software is a program w...

Perverse software: Perverse software is a program which causes hindrances in other programs execution in such a way resulting in modification or complete destruction of data w

Database reports, The first report, Report #1, is to be an ordered list of ...

The first report, Report #1, is to be an ordered list of the contents of the database, sorted in ascending order by a major field. Report #1 is to include all of the fields and rec

Basic computer structure, Basic computer structure: A computer is an el...

Basic computer structure: A computer is an electronic device, which can accept and process data by carrying out a set of stored instructions in sequence. This sequence of math

Disk output, Disk output : You will already have decided whether to u...

Disk output : You will already have decided whether to use a hard disk or floppies for storing data. An important point of disk management is to ensure a secure method of kee

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