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