Homework SourseI need to modify this MIPS program so that it can handle a s
I need to modify this MIPS program so that it can handle a string that includes blank spaces, includes punctuation, and includes both uppercase and lowercase characters. So i should be able to enter a phrase and it should beable to tell if that phrase is a palindrome or not.
And example would be \"Go hang a salami, I\'m a lasagna hog.\"
code:
## Daniel J. Ellard -- 02/21/94
## palindrome.asm -- read a line of text and test if it is a palindrome.
## Register usage
## $t1 - A.
## $t2 - B.
## $t3 - the character at address A.
## $t4 - the character at address B.
## $v0 - syscall parameter / return values.
## $a0 - syscall parameters.
## $a1 - syscall parameters.
.text
main: # SPIM starts by jumping to main.
## read the string S:
la $a0, string_space
li $a1, 1024
li $v0, 8 # load \"read_string\" code into $v0.
syscall
la $t1, string_space # A = S.
la $t2, string_space ## we need to move B to the end
length_loop: # of the string:
lb $t3, ($t2) # load the byte at addr B into $t3.
beqz $t3, end_length_loop # if $t3 == 0, branch out of loop.
addu $t2, $t2, 1 # otherwise, increment B,
b length_loop # and repeat the loop.
end_length_loop:
subu $t2, $t2, 2 ## subtract 2 to move B back past
# the ’\\0’ and ’\ ’.
test_loop:
bge $t1, $t2, is_palin # if A >= B, it’s a palindrome.
lb $t3, ($t1) # load the byte at addr A into $t3,
lb $t4, ($t2) # load the byte at addr B into $t4.
bne $t3, $t4, not_palin # if $t3 != $t4, not a palindrome.
# Otherwise,
addu $t1, $t1, 1 # increment A, 5.4. PALINDROME.ASM 75
subu $t2, $t2, 1 # decrement B,
b test_loop # and repeat the loop.
is_palin: ## print the is_palin_msg, and exit.
la $a0, is_palin_msg
li $v0, 4
syscall
b exit
not_palin:
la $a0, not_palin_msg ## print the is_palin_msg, and exit.
li $v0, 4
syscall
b exit
exit: ## exit the program:
li $v0, 10 # load \"exit\" into $v0.
syscall # make the system call.
## Here’s where the data for this program is stored:
.data
string_space: .space 1024 # reserve 1024 bytes for the string.
is_palin_msg: .asciiz \"The string is a palindrome.\ \"
not_palin_msg: .asciiz \"The string is not a palindrome.\ \"
## end of palindrome.asm
Solution
## Daniel J. Ellard - 02/21/94
## palindrome.asm - read a line of text and test if it is a palindrome.
## Register usage
## $t1 - A.
## $t2 - B.
## $t3 - the character at address A.
## $t4 - the character at address B.
## $v0 - syscall parameter / return values.
## $a0 - syscall parameters.
## $a1 - syscall parameters.
.text
main: # SPIM starts by jumping to main.
## read the string S:
la $a0, string_space
li $a1, 1024
li $v0, 8 # load \"read_string\" code into $v0.
syscall
la $t1, string_space # A = S.
la $t2, string_space ## we need to move B to the end
length_loop: # of the string:
lb $t3, ($t2) # load the byte at addr B into $t3.
beqz $t3, end_length_loop # if $t3 == 0, branch out of loop.
addu $t2, $t2, 1 # otherwise, increment B,
b length_loop # and repeat the loop.
end_length_loop:
subu $t2, $t2, 2 ## subtract 2 to move B back past
# the ’\\0’ and ’\ ’.
test_loop:
bge $t1, $t2, is_palin # if A >= B, it’s a palindrome.
lb $t3, ($t1) # load the byte at addr A into $t3,
lb $t4, ($t2) # load the byte at addr B into $t4.
bne $t3, $t4, not_palin # if $t3 != $t4, not a palindrome.
# Otherwise,
addu $t1, $t1, 1 # increment A, 5.4. PALINDROME.ASM 75
subu $t2, $t2, 1 # decrement B,
b test_loop # and repeat the loop.
is_palin: ## print the is_palin_msg, and exit.
la $a0, is_palin_msg
li $v0, 4
syscall
b exit
not_palin:
la $a0, not_palin_msg ## print the is_palin_msg, and exit.
li $v0, 4
syscall
b exit
exit: ## exit the program:
li $v0, 10 # load \"exit\" into $v0.
syscall # make the system call.
## Here’s where the data for this program is stored:
.data
string_space: .space 1024 # reserve 1024 bytes for the string.
is_palin_msg: .asciiz \"The string is a palindrome.\ \"
not_palin_msg: .asciiz \"The string is not a palindrome.\ \"
## end of palindrome.asm
