# a0 indirizzo base A
# a1 indirizzo base B
# a2  dim(A)=dim(B)=n
.data
	A: .word 1 2 3 4 5 6 7
	B: .word 7 6 5 4 3 2 1
	n: .word 7
.text
.globl main

main:
    addi $sp, $sp, -4
 	sw $ra, 0($sp)
	la $a0, A	      #$a0 = &A[0]
	la $a1, B	      #$a1 = &B[0]
	la $t0, n
	lw $a2, 0($t0)    #$a2 = n
	jal procedura
	lw $ra, 0($sp)
	addi $sp, $sp, 4
	jr $ra

procedura:
  addi $sp, $sp, -16
  sw $ra, 0($sp)
  sw $s0, 4($sp)
  sw $s1, 8($sp)
  sw $s2, 12($sp)
  add $v0, $0, $0
  add $s0, $a0, $0      # s0 = &A[0]
  add $s1, $a1, $0      # s1 = &B[0]
  add $s2, $a2, $0      # s2 = n
  add $t0, $0, $0       # inizializzazione indice for

startFor:
  slt $t2, $t0, $s2      # if(i<n) condizione for
  beq $t2, $0, endFor
  sll $t1, $t0, 2        # t1 = 4*i
  add $s1, $s1, $t1      # s1 = &B[i] = &B[0] + offset
  lw $t4, 0($s1)         # t4 = B[i] value
  add $s0, $s0, $t1      # s0 = &A[i]= &A[0] + offset
  lw $t5, 0($s0)         # t5 = A[i] value
  add $a3, $0, $t5       # a3 = A[i]
  jal f_T                # vado alla funzione ricorsiva
  add $t4, $t4, $v0      # B[i]+=f_T(A[i])
  addi $t0, $t0, 1       # incremento indice for
  j startFor

endFor:
  add $v0, $t4, $0     # return B[i]+=f_T(A[i])
  lw $ra, 0($sp)
  lw $s0, 4($sp)
  lw $s1, 8($sp)
  lw $s2, 12($sp)
  addi $sp, $sp, 16
  jr $ra               # return al main


f_T:
  addi $sp, $sp,-24
  sw $ra, 0($sp)
  sw $s0, 4($sp)
  sw $s1, 8($sp)
  sw $s3, 12($sp)
  sw $s4, 16($sp)
  sw $a3, 20($sp)       # salvo a3 = A[i] nello stack
  add $s4, $0, $0       # s4 come appoggio per la somma
  slti $t6, $a3, 3      # if(m<=2) = if(m<3)
  beq  $t6, $0, Else
  addi $v0, $0, 1       # $v0 = 1
  j endRic


Else:
  srl $a3, $a3, 1     # a3= a3/2
  jal f_T             # T(m/2)
  add $v0, $v0, $v0   # v0 = 3*T(m/2) scritto come $v0= $v0+ $v0+ $v0
  add $v0, $v0, $v0   # per evitare di usare un registro per inserirci 3 e usare mult
  add $s4, $0, $v0    # s4 = 3*T(m/2)
  lw $a3, 20($sp)     # ripristino A[i]
  srl $a3, $a3, 2     # A[i]/4
  jal f_T             # T(m/4)
  sll $v0, $v0, 1     # v0 = 2*T(m/4)
  add $v0, $v0, $s4   # v0 = 3*T(m/2) + 2*T(m/4)

endRic:
  lw $ra, 0($sp)
  lw $s0, 4($sp)
  lw $s1, 8($sp)
  lw $s3, 12($sp)
  lw $s4, 16($sp)   # non uso lw su a3 perchè tanto verrà aggiornata nel for con A[i+1]
  addi $sp, $sp, 24
  jr $ra            # return al for