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| 1 | .data | |
| 2 | A: .word 24 6 20 10 7 21 4 9 | |
| 3 | N: .word 8 | |
| 4 | ||
| 5 | .text | |
| 6 | .globl main | |
| 7 | ||
| 8 | main: | |
| 9 | la $a0, A # $a0 = A | |
| 10 | la $t0, N | |
| 11 | lw $a1, 0($t0) # $a1 = n | |
| 12 | # Alloco lo stack | |
| 13 | - | addi $sp, $sp, -12 |
| 13 | + | addi $sp, $sp, -4 |
| 14 | - | # Salvo i registri sullo stack |
| 14 | + | # Salvo $ra sullo stack |
| 15 | - | sw $ra, 8($sp) |
| 15 | + | sw $ra, 0($sp) |
| 16 | jal find_max # find_Max(A,n) | |
| 17 | # Fine procedura | |
| 18 | #Dealloco lo stack e carico $ra | |
| 19 | lw $ra, 0($sp) | |
| 20 | addi $sp, $sp, 4 | |
| 21 | - | lw $ra, 8($sp) |
| 21 | + | |
| 22 | - | addi $sp, $sp, 12 |
| 22 | + | |
| 23 | li $v0, 1 | |
| 24 | syscall | |
| 25 | jr $ra # return | |
| 26 | ||
| 27 | ||
| 28 | ||
| 29 | find_max: | |
| 30 | bne $a1, 1, else # if n != 1 goto else | |
| 31 | lw $v0, 0($a0) # $v0 = A[0] | |
| 32 | - | bne $a1, 1, else # is n != 1 goto else |
| 32 | + | |
| 33 | else: | |
| 34 | addi $a1, $a1, -1 # $a1 = n-1 | |
| 35 | # Alloco lo stack per salvare i registri $a e $ra | |
| 36 | - | addi $a1, $a1, -1 # n = n-1 |
| 36 | + | |
| 37 | - | sll $t0, $a1, 2 # $t0 = (n-1)*4 |
| 37 | + | |
| 38 | - | add $t0, $a0, $t0 # $t0 = &A[n-1] |
| 38 | + | |
| 39 | - | lw $a0, 0($t0) # $a0 = A[n-1] |
| 39 | + | |
| 40 | - | # Alloco lo stack per salvare i registri $a e $ra |
| 40 | + | |
| 41 | # Carico i registri e dealloco lo Stack tenendo $ra per la chiamata max | |
| 42 | lw $a1, 0($sp) # $a1 conterrà l'indice dell'elemento i-esimo da confrontare con maxSoFar | |
| 43 | lw $a0, 4($sp) # $a0 = A | |
| 44 | addi $sp, $sp, 8 | |
| 45 | - | jal max # max(A[n-1], find_max(A,n-1)) |
| 45 | + | # Mi preparo alla chiamata max |
| 46 | add $t0, $zero, $a0 # $t0 = A | |
| 47 | - | lw $ra, 8($sp) |
| 47 | + | add $a0, $zero, $v0 # $a0 = maxSoFar |
| 48 | - | addi $sp, $sp, 12 |
| 48 | + | sll $t1, $a1, 2 # carico in $t1 lo spiazzamento per accedere all' elem successivo dell'array |
| 49 | - | jr $ra # return max |
| 49 | + | add $t0, $t0, $t1 # $t0 = &A[i] |
| 50 | lw $a1, 0($t0) # $a1 = A[i] | |
| 51 | jal max | |
| 52 | # Dealloco lo stack e carico $ra | |
| 53 | - | lw $a0, 16($sp) # $a0 = A |
| 53 | + | lw $ra, 0($sp) |
| 54 | - | # Salvo sullo stack i registri $a e $ra |
| 54 | + | addi $sp, $sp, 4 |
| 55 | - | addi $sp, $sp, -12 |
| 55 | + | jr $ra #return |
| 56 | - | sw $ra, 8($sp) |
| 56 | + | |
| 57 | ||
| 58 | # Procedura foglia | |
| 59 | max: | |
| 60 | - | # Dealloco lo stack |
| 60 | + | slt $t0, $a0, $a1 |
| 61 | - | lw $ra, 8($sp) |
| 61 | + | beq $t0 ,$zero, old_max # if (maxSoFar >= A[i]) |
| 62 | - | addi $sp, $sp, 12 |
| 62 | + | add $v0, $zero, $a1 # $v0 = newMax |
| 63 | - | lw $a0, 4($sp) # Ricavo A[n-1] per il confronto e lo carico in $a0 |
| 63 | + | |
| 64 | - | slt $t0, $v0, $a0 |
| 64 | + | |
| 65 | - | beq $t0, $zero, max_soFar # $if A[i] > A[i+1] goto max_soFar |
| 65 | + | old_max: |
| 66 | - | add $v0, $zero, $a0 # max = new_Max |
| 66 | + | add $v0, $zero, $a0 # $v0 = oldMax |
| 67 | jr $ra |
