String Manipulation

The provided assignment content is a MIPS assembly code that accepts an input string and replaces certain characters (e.g., '#' with 'A', '%' with 'G', '$' with 'C', '&' with 'T') while preserving the original character count. The modified string is then outputted along with a newline and the replaced string.

.data
str: .space 40
fstr: .space 150
prompt: .asciiz "Input a string:"
output: .asciiz "Output string:"
newline: .asciiz "\n"
.text
.globl main
main:
# display prompt
li $v0, 4
la $a0, prompt
syscall
# accept input string
li $v0, 8
la $a0, str
li $a1, 64
syscall
li $t1, 0 # initiate index
li $t7, 0 # output index
loop:
li $t6 , 0
lb $t0 str($t1)
beqz $t0 exit
# check if "#"
li $t2, '#'
beq $t0, $t2, hash_to_a
nop
# check if "%"
li $t2, '%'
beq $t0, $t2, percent_to_g
nop
# check if "$"
li $t2, '$'

beq $t0, $t2, doller_to_c
nop
# check if "&"
li $t2, '&'
beq $t0, $t2, and_to_t
nop
#add $s0,$t1,$t7
sb $t0,fstr($t7)
addi $t7,$t7,1
addi $t1,$t1,1
# if not a "a", store it at current index in string less "a"
count
j loop
nop
replace:
sub $t5,$a1,32
beq $t5,$zero,space
bge $t6,$t5,loop
sb $a2,fstr($t7)
addi $t6,$t6,1
addi $t7,$t7,1
j replace
space :
#li $a2, '$'
subi $t1,$t1,1
subi $t1,$t1,1
lb $a2, str($t1)
sb $a2,fstr($t7)
addi $t7,$t7,1
addi $t1,$t1,1
addi $t1,$t1,1
jal loop
hash_to_a:

addi $t1,$t1,1
lb $a1 str($t1)
subi $t1,$t1,1
li $a2, 'A'
addi $t1,$t1,1
addi $t1,$t1,1
jal replace
percent_to_g:
addi $t1,$t1,1
lb $a1 str($t1)
subi $t1,$t1,1
li $a2, 'G'
addi $t1,$t1,1
addi $t1,$t1,1
jal replace
doller_to_c:
addi $t1,$t1,1
lb $a1 str($t1)
subi $t1,$t1,1
li $a2, 'C'
addi $t1,$t1,1
addi $t1,$t1,1
jal replace
and_to_t:
addi $t1,$t1,1
lb $a1 str($t1)
subi $t1,$t1,1
li $a2, 'T'
addi $t1,$t1,1
addi $t1,$t1,1
jal replace
exit:
li $v0, 4 # output a newline
la $a0, newline
syscall
li $v0, 4
la $a0, output

syscall
li $v0, 4
la $a0, fstr
syscall
li $v0, 10 # exit program
syscall
nop