Question

How do I write a program in MIPS that will change all the characters in a string into lowercase.

For instance: string: " CANBERRA AUSTRALIA"

Output: "canberra australia"

Answer 1

Screenshot of the code:-

Screenshot of the output(in Mars Simulator):-

MIPS code to copy(with comments):-

.data
in_str: .asciiz "Enter the string: "
out_str: .asciiz "Capitalized String is: "
buff: .space 80 #this is the buffer

.text

main:
la $a0, in_str # Load and print string asking for string
li $v0, 4
syscall  
  
li $v0, 8 # Get the input
la $a0, buff # load the byte space into the address
li $a1, 80 # allot the byte space for string
syscall
move $s0, $a0 # save string
  
li $v0, 4
li $t0, 0

#Loop to convert to lowercase
loop:
lb $t1, buff($t0) #Load byte from 't0'th position in the buffer into $t1
beq $t1, 0, exit #If input ends, go to exit
bge $t1, 'A', maybe_not_capital #If greater than A, go to maybe_not_capital
ble $t1,'A',other_chars #If less than A,go to other_chars
  
j upper_to_lower
  
upper_to_lower:
addi $t1,$t1,32
sb $t1, buff($t0) #Store it back to 't0'th position in buffer
  
maybe_not_capital:
blt $t1, 'Z',upper_to_lower #If less than Z, go to upper_to_lower
addi $t0, $t0, 1 #else, increment $t0 and continue
j loop
  
other_chars:
beq $t1,' ',space #If it is space,then go to space
  
space:
addi $t0, $t0, 1
j loop
              
exit:
la $a0, out_str # load and print the capitalised string
li $v0, 4
syscall

move $a0, $s0   
li $v0, 4 # print string
syscall
li $v0, 10 # end program
syscall