You will learn to code procedures and follow the MIPS register conventions for this project.

There will be three procedures/functions in your code: the main()procedure, the revCase()procedure and the findMin()function. Each must have the defined parameters and functionality as explained in these specifications.You are given a starter file revCaseMin.asm to add your code to; some of the system calls for output and input are already done. Write an assembly prog ram revCaseMin.asm where :

1.The main()procedure

a. prompts the user to enter 30 characters and stores these characters as a character array into

memory.

b. invokes the revCase()procedure that accepts as an argument the base address of this character array and the number of characters in this array.

2.The revCase()procedure

a. Has two parameters, the base address of a character array and the number of characters in this array. You may not hard code the argument value 30 within this procedure but instead use the 2^nd parameter of the procedure.Recall registers $a0 and $a1will be populated by the calling

procedure main().

b. Calculates the reverse case of the characters entered by the user placing them,by using a loop,in to a character array and prints the characters in reverse case.If a loop is not used,many

points are deducted.

c.Invokes the function findMin()passing in the required arguments and uses the return value

from findMin(). The return value from findMin()is the minimum character entered by the user

after the character string is reversed in case. See details that follow for findMin().

d.Prints the minimum character returned from the function findMin()

3.The findMin()function has two parameters : the first parameter is the base address of the character array it will examine and the second is the number of characters that it will examine

to find the minimum ASCII character. findMin()returns in $v0 the minimum ASCII character from the string it examined. You may not hard code the value 30 but must instead use the value in the first argument register $a1 to aid in the looping structure for finding the minimum character.

4. All register conventions and procedure invocation conventions must be adhered--review the MIPS reference sheet for preserving registers across procedure calls and these conventions.

5.Use the starter code file,revCaseMin.asm, making the necessary modifications for this project. Remember, to place YOUR name at the top of the code.

example:

Please enter 30 characters (upper/lower case mixed):aBcDeFgHiJkLmNoPqRsTuVwXyZAbCd

Your string in reverse case is:AbCdEfGhIjKlMnOpQrStUvWxYzaBcD

The min ASCII character after reversal is: B

Given Code

# Starter code for reversing the case of a 30 character input.

# Put in comments your name and date please. You will be

# revising this code.

#

# Created by Dianne Foreback

# Students should modify this code

#

# This code displays the authors name (you must change

# outpAuth to display YourFirstName and YourLastName".

#

# The code then prompts the user for input

# stores the user input into memory "varStr"

# then displays the users input that is stored in"varStr"

#

# You will need to write code per the specs for

# procedures main, revCase and function findMin.

#

# revCase will to reverse the case of the characters

# in varStr. You must use a loop to do this. Another buffer

# varStrRev is created to hold the reversed case string.

#

# Please refer to the specs for this project, this is just starter code.

#

# In MARS, make certain in "Settings" to check

# "popup dialog for input syscalls 5,6,7,8,12"

#

.data # data segment

.align 2 # align the next string on a word boundary

outpAuth: .asciiz "This is YourFirstName YourLastName presenting revCaseMin. "

outpPrompt: .asciiz "Please enter 30 characters (upper/lower case mixed): "

.align 2 #align next prompt on a word boundary

outpStr: .asciiz "You entered the string: "

.align 2 # align users input on a word boundary

varStr: .space 32 # will hold the user's input string thestring of 20 bytes

# last two chars are \0 (a new line and null char)

# If user enters 31 characters then clicks "enter" or hits the

# enter key, the will not be inserted into the 21st element

# (the actual users character is placed in 31st element). the

# 32nd element will hold the \0 character.

# .byte 32 will also work instead of .space 32

.align 2 # align next prompt on word boundary

outpStrRev: .asciiz "Your string in reverse case is: "

.align 2 # align the output on word boundary

varStrRev: .space 32 # reserve 32 characters for the reverse case string

.align 2 # align on a word boundary

outpStrMin: .asciiz "The min ASCII character after reversal is: "

#

.text # code section begins

.globl main

main:

#

# system call to display the author of this code

#

la $a0,outpAuth # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

#

# system call to prompt user for input

#

la $a0,outpPrompt # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

#

# system call to store user input into string thestring

#

li $v0,8 # system call 8 for read string needs its call number 8 in $v0

# get return values

la $a0,varStr # put the address of thestring buffer in $t0

li $a1,32 # maximum length of string to load, null char always at end

# but note, the is also included providing total len < 22

syscall

#move $t0,$v0 # save string to address in $t0; i.e. into "thestring"

#

# system call to display "You entered the string: "

#

la $a0,outpStr # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

#

# system call to display user input that is saved in "varStr" buffer

#

la $a0,varStr # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

#

# Your code to invoke revCase goes next

#

# Exit gracefully from main()

li $v0, 10 # system call for exit

syscall # close file

################################################################

# revCase() procedure can go next

################################################################

# Write code to reverse the case of the string. The base address of the

# string should be in $a0 and placed there by main(). main() should also place into

# $a1 the number of characters in the string.

# You will want to have a label that main() will use in its jal

# instruction to invoke revCase, perhaps revCase:

#

revCase:

#

# After reversing the string, you may print it with the following code.

# This is the system call to display "Your string in reverse case is: "

la $a0,outpStrRev # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

# system call to display the user input that is in reverse case saved in the varRevStr buffer

la $a0,varStrRev # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

#

# Your code to invoke findMin() can go next

# Your code to return to the caller main() can go next

################################################################

# findMin() function can go next

################################################################

# Write code to find the minimum character in the string. The base address of the

# string should be in $a0 and placed there by revCase. revCase() should also place into

# $a1 the number of characters in the string.

# You will want to have a label that revCase() will use in its jal

# instruction to invoke revCase, perhaps findMin:

#

#

findMin:

# write use a loop and find the minimum character

#

# system call to display "The min ASCII character after reversal is: "

la $a0,outpStrMin # system call 4 for print string needs address of string in $a0

li $v0,4 # system call 4 for print string needs 4 in $v0

syscall

# write code for the system call to print the the minimum character

# write code to return to the caller revCase() can go next