Loops in MIPS

Author: rohitdwivedula

palindrome.asm

@@ -0,0 +1,58 @@
+# check if user provided string is palindrome
+
+.data
+
+welcomeMsg: .asciiz "Enter a string: "
+userString: .space 256
+newline: .asciiz "\n"
+yes: .asciiz "IS PALINDROME"
+no: .asciiz "NOT PALINDROME"
+
+.text
+
+main:
+	li $v0, 4
+	la $a0, welcomeMsg
+	syscall
+	la $a0, userString
+	li $a1, 256
+	li $v0, 8
+	syscall
+
+	li $v0, 4
+	la $a0, userString
+	syscall
+	lb $t5, newline
+
+	# store address of last element of userString in $a1
+	add $t1, $a0, $zero 
+	lengthZero:
+		lb $t3, ($t1)
+		addi $t1, $t1, 1
+		beq $t3, $t5, done # this step is required as MIPS reads newline after string	
+		bne $t3, $zero, lengthZero
+	done: 
+	addi $t1, $t1, -2
+	# check if palindrome
+	add $t0, $a0, $zero
+	
+	check_letter:
+		lb $t2, ($t0)
+		lb $t3, ($t1)
+		bne $t2, $t3, notPalindrome
+		addi $t0, $t0, 1
+		addi $t1, $t1, -1
+		blt $t0, $t1, check_letter
+
+	li $v0, 4
+	la $a0, yes
+	syscall
+	j endProgram
+
+	notPalindrome:
+		li $v0, 4
+		la $a0, no
+		syscall
+	endProgram:
+	li $v0, 10
+	syscall

print_array.asm

@@ -0,0 +1,28 @@
+.data
+
+list: .word 17, 5, 92, 87, 41, 10, 23, 55, 72, 36
+listSize: .word 10
+msg: .asciiz "Array is: "
+space: .asciiz " "
+
+.text
+
+lw $t0, listSize
+la $a2, list
+li $t1, 0
+
+print:
+	beq $t1, $t0, exit
+	lw $a0, ($a2)
+	li $v0, 1
+	syscall
+	li $v0, 4
+	la $a0, space
+	syscall
+	addi $a2, $a2, 4
+	addi $t1, $t1, 1
+	j print
+	
+exit:
+li $v0, 10
+syscall

reverse_string.asm

@@ -0,0 +1,47 @@
+# reverse a user inputted string in place and print it
+
+.data
+
+welcomeMsg: .asciiz "Input string: "
+userString: .space 256
+newline: .asciiz "\n"
+
+.text
+
+li $v0, 4
+la $a0, welcomeMsg
+syscall
+
+li $v0, 8
+la $a0, userString
+li $a1, 256
+syscall
+
+li $v0, 4
+syscall
+
+add $t0, $a0, $zero
+lb $t5, newline
+find_end:
+	lb $t1, ($t0)
+	addi $t0, $t0, 1
+	beq $t5, $t1, end
+	bne $t1, $zero, find_end
+end:
+	addi $t0, $t0, -2
+
+swap:
+	lb $t2, ($a0) 
+	lb $t3, ($t0)
+	sb $t2, ($t0)
+	sb $t3, ($a0)
+	addi $a0, $a0, 1
+	addi $t0, $t0, -1
+	ble $a0, $t0, swap
+
+li $v0, 4
+la $a0, userString
+syscall
+
+li $v0, 10
+syscall