lab 1 ScM

.data

# Problem: The sum of an array's elements
.align 2                            # will make the following data to be aligned on 4 bytes (2^2)
numere: .word 1,2,3,4,5,6,7,8,9,10  # a word is written on 4 bytes
                                    # starting address is the same as the label (numere)

outs: .asciiz "The sum is: "        # the string to be printed

quot: .asciiz "Quotient: "
remn: .asciiz "Remainder: "

.text

    xor     $t0,    $t0,    $t0     # $t0 = 0  -> the sum
    li      $t1,    9               # $t1 = 9 -> the offset numere+2^offset

loop:
    li      $t5,    4               # the skip value
    la      $t4,    numere          # $t2 = numere

    mul     $t3,    $t5,    $t1     # $t3 = $t5 * $t1 -> index = offset * 4
    add     $t5,    $t4,    $t3     # $t5 = $t4 + $t3 -> address = numere + index

    lw      $t2,    ($t5)           # $t2 = MEM(numere[offset])
                                    # if we didn't put parantheses, the assembler would have thought that we want to load the ADDRESS value (0xWhatever)

    add     $t0,    $t0,    $t2     # $t0 = $t0 + $t2 -> sum = sum + numere[offset]

    sub     $t1,    $t1,    1       # $t1 = $t1 - 1 -> offset = offset - 1
    bgez    $t1,    loop            # if offset >= 0 then loop

    puts    outs                    # print the string
    puti    $t0                     # print the sum

    putc    '\n'                    # print two new lines
    putc    '\n'


# alternatively, we could have used the following code to print the sum
    li      $v0,    4               # $v0 = 4 -> the print string syscall
    la      $a0,    outs            # $a0 = outs -> the string to be printed
    syscall                         # print the string

    li      $v0,    1               # $v0 = 1 -> the print integer syscall
    move    $a0,    $t0             # $a0 = $t0 -> the integer to be printed
    syscall                         # print the integer

    li      $t1,    10
    div     $t0,    $t1             # Lo = $t0 / $t1, Hi = $t0 % $t1
    mflo    $t2                     # $t2 = Lo -> $t2 = $t0 / $t1
    mfhi    $t3                     # $t3 = Hi -> $t3 = $t0 % $t1

    putc    '\n'                    # print a new line
    puts    quot                    # print the string
    puti    $t2                     # print the integer $t2

    putc    '\n'                    # print a new line
    puts    remn                    # print the string
    puti    $t3                     # print the integer $t3

    li      $v0,    10              # $v0 = 10 -> the exit syscall
    syscall                         # exit