lab 2 ScM

.data

.align 2                                        # 2^2 = 4 bytes per item
numerePrime: .space 100                         # init space for 100 elements => 100/4 = 25 elements

.text

    li      $t4,        0                       # counter
    li      $t5,        25                      # total number of elements
    li      $a1,        2                       # N a0 is avoided because it is used for return value of functions
    la      $t6,        numerePrime             # address of array

cauta:
    jal     EstePrim                            # call function (jump and link)
    beqz    $s0,        nu_e_prim               # if s0 == 0, then n is not prime

e_prim:
    puti    $a1
    putc    ' '
    sw      $a1,        ($t6)                   # store a1 in array
    addi    $t6,        $t6,            4       # t6 += 4
    addi    $t4,        $t4,            1       # t4++ (counter++)

nu_e_prim:
    addi    $a1,        $a1,            1       # a1++ (n++)
    sge     $t7,        $t4,            $t5     # t7 = 1 if t4 >= t5
    beqz    $t7,        cauta                   # if t7 == 0, then continue

sfarsit:
    done

# input: $a0 - $a3. The other registers are not preserved.
# $a1 = n
# outuput: $s0 - $s8.
# $s0 = 1 if n is prime, 0 otherwise
EstePrim:
    li      $t0,        2                       # t0 = 2 (new counter)

repeta:
    sge     $t3,        $t0,            $a1     # t3 = 1 if t0 >= a1(n)
    bnez    $t3,        gata_e_prim             # if t3 == 1, then n is prime

    div     $a1,        $t0                     # n / t0
    mfhi    $t1                                 # t1 = n % t0

    addi    $t0,        $t0,            1       # t0++
    beqz    $t1,        gata_nu_e_prim          # if t1 == 0, then n is not prime

    j       repeta                              # jump to repeta (continue)
gata_nu_e_prim:
    li      $s0,        0                       # n is not prime
    j       iesire                              # jump to iesire

gata_e_prim:
    li      $s0,        1                       # n is prime
    j       iesire                              # jump to iesire

iesire:
    jr      $ra                                 # jump register to return address