.text
.globl main

main:
      addi $sp, $sp, 4
      sw $ra, 0($sp)
      la $a0, A
      la $a1, B
      lw $a2, N
      jal proc
      lw $ra, 0($sp)
      jr $ra

proc:

     addi $sp, $sp, -16      # alloco 16 bytes sullo stack
     sw $ra, 12($sp)
     sw $s0, 0($sp)
     sw $s1, 8($sp)
     sw $s2, 4($sp)

     add $s0, $zero, $a0      # $s0 = &(A[0])
     add $s1, $zero, $a1      # $s1 = &(B[0])
     add $s2, $zero, $a2      # $s2 = n
     add $t0, $zero, $zero    # t0 = i


loop:

     lw $t1, 0($s1)           # $t1 = B[i]
     addi $t2, $t0, 1         # $t2 = i+1
     add $t3, $zero, $zero    # $t3 = j
     add $v0, $zero, $zero    # inizializzo $v0 (somma) a 0
     jal somma                # somma restituita in $v0
     add $s0, $a0, $zero      # ripristino &A[0]
     add $t1, $t1, $v0        # $t1 = B[i] + somma dei primi i elementi di A
     sw $t1, 0($s1)           # inserisco il nuovo valore in B[i]
     addi $t0, $t0, 1         # i = i+1
     addi $s1, $s1, 4         # incremento &B[i]
     beq $t0, $s2, Exit       # if (i = n) goto Exit
     j loop


somma:

      lw $t4, 0($s0)          # $t4 = A[i]
      add $v0, $v0, $t4       # somma = somma + A[i]
      addi $t3, $t3, 1        # j = j+1
      addi $s0, $s0, 4        # incremento &A[i]
      beq $t3, $t2, Exitsomma # if j = i+1 goto Exitsomma
      j somma


Exitsomma:
      jr $ra

Exit:

     lw $ra, 12($sp)
     lw $s0, 0($sp)
     lw $s1, 8($sp)
     lw $s2, 4($sp)
     addi $sp, $sp, 16       # dealloco 16 bytes sullo stack
     jr $ra


.data

     A: .word 3 2 5 1
     B: .word 2 6 1 3
     N: .word 4