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- .data
- v: .word 3, 10, 8, 2, 7, 1, 5, 9, 6, 4
-
-
- # swap(int i, int j) : swaps elements of v[]
- # at positions i and j
- # $a0 = i
- # $a1 = j
- # $s0 = v
- .text
- swap:
- # intro - stack-frame
- addi $sp, $sp, -28
- sw $ra, 24($sp)
- sw $fp, 20($sp)
-
- sw $s0, 16($sp) # v
- sw $t0, 12($sp) # temp
- sw $t1, 8($sp) # *v[i]
- sw $t2, 4($sp) # *v[j]
- sw $t3, 0($sp) # buffer
- addi $fp, $sp, 24
-
-
- move $t1, $s0 # pointer assignements
- sll $a0, $a0, 2
- add $t1, $t1, $a0
- move $t2, $s0
- sll $a1, $a1, 2
- add $t2, $t2, $a1
-
- lw $t0, 0($t1) # temp = v[i]
- lw $t3, 0($t2) # v[i] = v[j]
- sw $t3, 0($t1)
- sw $t0, 0($t2) # v[j] = temp
-
- # epilogue - stack-frame
- lw $t3, 0($sp)
- lw $t2, 4($sp)
- lw $t1, 8($sp)
- lw $t0, 12($sp)
- lw $s0, 16($sp)
-
- lw $fp, 20($sp)
- lw $ra, 24($sp)
- addi $sp, $sp, 28
- jr $ra
-
- # partition(int f, int l) : partitions elements in vector v[]
- # between positions f and l, using as pivot the element v[l], such
- # that
- # i < p ==> v[i] <= v[p]
- # i > p ==> v[p] < v[i]
- # The function returns the position p of the pivot.
- # $a0 = f
- # $a1 = l
- # $s0 = v
- # $v0 = p
- .text
- partition:
- # intro - stack-frame
- addi $sp, $sp, -40
- sw $ra, 36($sp)
- sw $fp, 32($sp)
-
- sw $s0, 28($sp) # v
- sw $s1, 24($sp) # pivot
- sw $s2, 20($sp) # i
- sw $s3, 16($sp) # j
- sw $s4, 12($sp) # a0 (f)
- sw $s5, 8($sp) # a1 (l)
- sw $t0, 4($sp)
- sw $t1, 0($sp)
- addi $fp, $sp, 36
-
- move $s4, $a0
- move $s5, $a1
- move $t0, $s0 # make *v[l]
- move $t1, $a1 # t1 = l
- sll $t1, $t1, 2 # t1 *= 4
- add $t0, $t0, $t1
- lw $s1, 0($t0) # pivot = v[l]
-
- move $s2, $s4 # i = f;
-
- # for () {
- move $s3, $s4 # j = f;
- _part_loop0:
- slt $t0, $s3, $s5 # j < l
- beq $t0, $0, _part_loop_end
- move $t0, $s0 # make *v[j]
- move $t1, $s3
- sll $t1, $t1, 2
- add $t0, $t0, $t1
- lw $t1, 0($t0) # t1 = v[j]
- # if (v[j] < pivot)
- slt $t0, $t1, $s1
- beq $t0, $0, _part_loop_else
-
- move $a0, $s2 # swap (i, j);
- move $a1, $s3
- jal swap
- addi $s2, 1 # i++
-
- _part_loop_else:
- addi $s3, 1 # j++
- j _part_loop0 # }
- _part_loop_end:
- move $a0, $s2 # swap (i, l)
- move $a1, $s5
- jal swap
-
- move $v0, $s2 #return i
-
- # epilogue - stack-frame
- lw $t1, 0($sp)
- lw $t0, 4($sp)
- lw $s5, 8($sp)
- lw $s4, 12($sp)
- lw $s3, 16($sp)
- lw $s2, 20($sp)
- lw $s1, 24($sp)
- lw $s0, 28($sp)
-
- lw $fp, 32($sp)
- lw $ra, 36($sp)
- addi $sp, $sp, 40
- jr $ra
-
-
- # qsort(int f, int l) : sorts the elements of v[]
- # between positions f:l
- # $a0 = f
- # $a1 = l
- # $s0 = v
- .text
- qsort: # qsort entry point
- # intro - stack-frame with 4byte local var @ fp
- addi $sp, $sp, -28 # qsort
- sw $ra, 24($sp)
- sw $fp, 20($sp)
-
- sw $s0, 16($sp) # v
- sw $s2, 12($sp) # a0 (f)
- sw $s3, 8($sp) # a1 (l)
- sw $t0, 4($sp)
- addi $fp, $sp, 24
-
- move $s2, $a0 # get f, l
- move $s3, $a1
- # if (f < l) {
- slt $t0, $s2, $s3
- beq $t0, $0, _qsort_end
-
- move $a0, $s2 # pivot = partition(f, l);
- move $a1, $s3
- jal partition
- sw $v0, 0($sp)
-
- move $a0, $s2 # qsort(f, pivot - 1);
- lw $t0, 0($sp)
- addi $t0, $t0, -1
- move $a1, $t0
- jal qsort
-
- lw $t0, 0($sp) # qsort(pivot + 1, l);
- addi $t0, $t0, 1
- move $a0, $t0
- move $a1, $s3
- jal qsort
- # }
- _qsort_end:
- # epilogue - stack-frame
- lw $t0, 4($sp)
- lw $s3, 8($sp)
- lw $s2, 12($sp)
- lw $s0, 16($sp)
-
- lw $fp, 20($sp)
- lw $ra, 24($sp)
- addi $sp, $sp, 28
- jr $ra # return to caller
-
-
- .text
- .globl main
- main:
- # intro - stack-frame
- addi $sp, $sp, -12 # main
- sw $ra, 8($sp)
- sw $fp, 4($sp)
- sw $s0, 0($sp)
- addi $fp, $sp, 8
-
- li $t0, 10
-
- li $a0, 0
- li $a1, 9
- la $s0, v
- jal qsort
-
- # epilogue - stack-frame
- lw $s0, 0($sp)
- lw $fp, 4($sp)
- lw $ra, 8($sp)
- addi $sp, $sp, 12
- jr $ra
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