| 1 | .data |
| 2 | input: .space 50 |
| 3 | input_string: .asciiz "Saisir un mot ? " |
| 4 | msg_palindrome_part_1: .asciiz "Le mot " |
| 5 | msg_palindrome_part_2: .asciiz " un palindrome" |
| 6 | msg_is: .asciiz " est" |
| 7 | msg_is_not: .asciiz " n'est pas" |
| 8 | newline: .asciiz "\n" |
| 9 | |
| 10 | .text |
| 11 | main: |
| 12 | jal input_word |
| 13 | jal clean_and_length_word |
| 14 | jal isPalindrome |
| 15 | li $v0, 10 |
| 16 | syscall |
| 17 | |
| 18 | input_word: |
| 19 | la $a0, input_string |
| 20 | li $v0, 4 |
| 21 | syscall |
| 22 | li $v0, 8 |
| 23 | la $a0, input |
| 24 | li $a1, 50 |
| 25 | syscall |
| 26 | jr $ra |
| 27 | |
| 28 | clean_and_length_word: |
| 29 | la $s4, ($zero) # word length |
| 30 | la $s0, input # $s0 contains base address of the string buffer |
| 31 | addi $s3, $0, '\n' # $s3 = '\n' |
| 32 | loop1: |
| 33 | lb $s1, 0($s0) # load character into $s1 |
| 34 | beq $s1, $s3, end1 # break if byte is newline |
| 35 | addi $s0, $s0, 1 # increment buffer address |
| 36 | addi $s4, $s4, 1 |
| 37 | j loop1 |
| 38 | end1: |
| 39 | sb $0, 0($s0) # replace newline with 0 |
| 40 | la $a2, ($s4) |
| 41 | jr $ra |
| 42 | |
| 43 | isPalindrome: |
| 44 | # Check base case |
| 45 | slti $t0, $a2, 2 |
| 46 | bne $t0, $zero, returnTrue |
| 47 | |
| 48 | # Make sure first and last are equal |
| 49 | lb $t0, 0($a0) |
| 50 | addi $t1, $a2, -1 |
| 51 | add $t1, $t1, $a0 |
| 52 | lb $t1, 0($t1) |
| 53 | bne $t0, $t1, returnFalse |
| 54 | |
| 55 | # Shift pointer, length, recurse |
| 56 | addi $a2, $a2, -2 |
| 57 | addi $a0, $a0, 1 |
| 58 | j isPalindrome |
| 59 | |
| 60 | returnFalse: |
| 61 | addi $v0, $zero, 0 |
| 62 | addi $sp, $sp, -4 |
| 63 | sw $ra, 0($sp) |
| 64 | jal display_not_palindrome |
| 65 | lw $ra, 0($sp) |
| 66 | addi $sp, $sp, 4 |
| 67 | jr $ra |
| 68 | |
| 69 | returnTrue: |
| 70 | addi $v0, $zero, 1 |
| 71 | addi $sp, $sp, -4 |
| 72 | sw $ra, 0($sp) |
| 73 | jal display_palindrome |
| 74 | lw $ra, 0($sp) |
| 75 | addi $sp, $sp, 4 |
| 76 | jr $ra |
| 77 | |
| 78 | display_palindrome: |
| 79 | la $a0, msg_palindrome_part_1 |
| 80 | li $v0, 4 |
| 81 | syscall |
| 82 | la $a0, input |
| 83 | li $v0, 4 |
| 84 | syscall |
| 85 | la $a0, msg_is |
| 86 | li $v0, 4 |
| 87 | syscall |
| 88 | la $a0, msg_palindrome_part_2 |
| 89 | li $v0, 4 |
| 90 | syscall |
| 91 | la $a0, newline |
| 92 | li $v0, 4 |
| 93 | syscall |
| 94 | jr $ra |
| 95 | |
| 96 | display_not_palindrome: |
| 97 | la $a0, msg_palindrome_part_1 |
| 98 | li $v0, 4 |
| 99 | syscall |
| 100 | la $a0, input |
| 101 | li $v0, 4 |
| 102 | syscall |
| 103 | la $a0, msg_is_not |
| 104 | li $v0, 4 |
| 105 | syscall |
| 106 | la $a0, msg_palindrome_part_2 |
| 107 | li $v0, 4 |
| 108 | syscall |
| 109 | la $a0, newline |
| 110 | li $v0, 4 |
| 111 | syscall |
| 112 | jr $ra |