MIPS printing strange empty square

Question

I am writing a code to read a NxN array using macros in MIPS, it has no problems reading, but when the function printString is called after a few uses, it starts printing a strange square. I found that commenting the line sw $v0, ($t9) in readArray will make the function print as expected, however the contents that were read won't be saved anymore (and the function will be useless).

My code is the following:

.data

.macro printString(%string)
    .data
        string: .asciiz %string
    .text
        li $a0, 0
        li $v0, 0
        la $a0, string
        li $v0, 4
        syscall
.end_macro

.macro printInt(%int)
    .text
        li $a0, 0
        li $v0, 0
        add $a0, $zero, %int
        li $v0, 1
        syscall
.end_macro

.macro alloc(%size)
    .text
        li $a0, 0
        li $v0, 0
        add $a0, $zero, %size
        li $v0, 9
        syscall
.end_macro

.macro end()
    .text
        li $v0, 10
        syscall
.end_macro

.macro readInt()
    .text
        li $v0, 5
        syscall
.end_macro

.macro readArray(%array, %size)
    .data
        array: %array
    .text
        rAMain:
            la $t4, array
            add $t5, $zero, %size
            li $t6, 0
            li $t7, 0
        rALoop:
            arrayIndex($t4, $t5, $t6, $t7)
            move $t9, $v0
            printString("Write a value:[")
            printInt($t6)
            printString("][")
            printInt($t7)
            printString("]: ")
            readInt()
            sw $v0, ($t9)
            addi $t7, $t7, 1
            blt $t7, $t5, rALoop
            li $t7, 0
            addi $t6, $t6, 1
            blt $t6, $t5, rALoop    
.end_macro

.macro arrayIndex(%array, %columnNumber, %i, %j)
    .data
        array: %array
    .text
        la $t0, array
        add $t1, $zero, %i
        add $t2, $zero, %j
        add $t3, $zero, %columnNumber
        mul $v0, $t1, $t3
        add $v0, $v0, $t2
        sll $v0, $v0, 2 
        add $v0, $t0, $v0       
.end_macro

.text
    main:
        jal readN
        alloc($s1)
        move $s0, $v0
        readArray($s0, $s1)
        end()
        
    readN:   ###### 
        printString("Write the value of N: ")
        readInt()
        move $s1, $v0
        jr $ra

Picture of the error:

Answer 1

Usage of:

.data
    array: %array

in your readArray macro does not allocate any storage when the corresponding parameter is a register — in fact, array: $t0 doesn't make any sense to me, but somehow MARS allocated zero bytes of storage after the array label without complaining of syntax error.

The data declarations .data ... array: are global declarations, which are performed at compile/assemble time, rather than dynamic allocations performed at runtime.  This is one reason I'm surprised that MARS accepts a register name as an argument here, but none-the-less, it surely isn't doing what you want.