Program

Purpose

Program Statement

• Prints the string "Enter string: ".
• Reads a character string one character at a time until end of line ('\n').
• Changes the case of each alphabetic character (e.g., 'A' -> 'a' and 'b' -> 'B').
• Leaves other characters unchanged (e.g., '9' -> '9').
• Prints the string "The new string is: ".
• Prints the new characters including a terminating '\n'.
• Exits after processing one string.

Example Runs

Enter string:
bUCky wIns 28-0!
The new string is:
BucKY WiNS 28-0!

Enter string:
0Oo I1i
The new string is:
0oO i1I

Requirements

1. Your program must contain adequate comments (documentation). Such comments include your name and section number at the top of the program. They also include a description of the program, as well as variable descriptions and comments about the code itself.
2. Your program must use at least one procedure!!!
3. Use Pentium instructions only! Do not use SASM instructions! Do not include the statement

     include sasmacros.inc

in your program. Instead, put in the statement

     include Pmacros.inc

You will need to get a copy of the file Pmacros.inc. It is found on a link on the textbook website.
 
4. You must read all characters of the input string before any characters of the output string are printed out.
5. Input character strings will be 80 characters or less. Store the characters of the string in an array.

Hints

• Take a look at the textbook web page under programming advice. This page has been appended to include a section on dealing with Pentium assembly language code.
• Note that the operation of the I/O instructions work a little bit different for Pentium programs than they did for SASM programs.




---

Homework

1. (10 points, 5 each)

Consider a two dimensional array of IEEE double-precision floating-point numbers (eight bytes each). Let the row index, the first index, vary from 2 to 8, while the column index varies from 0 to 5. Assume that the array is stored in row-major order beginning at address 0x00000040.
a) How many bytes does it take to store myarray?
b) Give the hexadecimal address of myarray[6,2].
2. (5 points)

A pointer to an element of an array is in register edx. Give a single Pentium instruction that will subtract 4 from this array element.
 
3. (25 points)
Write a sample instruction  that illustrates each of the following addressing modes.  Show memory and registers before and after each instruction is executed.  Use the same initial values of memory and registers for each part of the problem.
a)  register mode
b) immediate mode
c) register direct
d) base displacement
e) direct addressing

Handing In the Assignment

For this assignment, you will need to turn in a single zip file. To make grading easier, please name the file hw5.GX.zip.  No printout will be turned in.