Calcolatrice.s

ADD1: add $v0, $a0, $a1
      jr $ra
SUB1: sub $v0, $a0, $a1
      jr $ra
PRO1: mul $v0, $a0, $a1
      jr $ra
DIV1: div $v0, $a0, $a1
      jr $ra
    .data
Addn: .asciiz "1. Addizione\n"
Subn: .asciiz "2. Sottrazione\n"
Prot: .asciiz "3. Moltiplicazione\n"
Divn: .asciiz "4. Divisione\n"
null: .asciiz "Valore non valido\n"
numeri: .word 1, 2, 3, 4

    .text
    .globl main
main:
    li $v0, 4
    la $a0, Addn
    syscall

    li $v0, 4
    la $a0, Subn
    syscall

    li $v0, 4
    la $a0, Prot
    syscall

    li $v0, 4
    la $a0, Divn
    syscall

    la $s0, numeri
    lw $s1, 0($s0)
    lw $s2, 4($s0)
    lw $s3, 8($s0)
    lw $s4, 12($s0)

    j LOAD

LOAD:
      li $v0, 5
      syscall
      move $t4, $v0
      move $s5, $t4

      li $v0, 5
      syscall
      move $t5, $v0
      move $s5, $t5

      li $v0, 5
      syscall
      move $t6, $v0
      move $s6, $t6

      j ADD

ADD: beq $s5, $s1, SUB
     jal ADD1

SUB: beq $s5, $s2, PRO
     jal SUB1

PRO: beq $s5, $s3, DIV
     jal PRO1

DIV: beq $s5, $s4, END
     jal DIV1

END: li $v0, 4
     la $a0, null
     j LOAD

    move $t1, $v0
    move $a0, $t1
    li $v0, 1
    syscall