37 lines
1.4 KiB
NASM
37 lines
1.4 KiB
NASM
.data
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.text
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main:
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li $v0, 5 # read in
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syscall
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move $s0, $v0 # s0 is the n
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move $a0, $s0 # set the first call arg as n
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jal hanoi # call proc
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move $a0, $v0 # print out
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li $v0, 1
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syscall
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li $a0, 0
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li $v0, 17
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syscall
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hanoi:
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li $t0, 1
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ble $a0, $t0, hanoi_bottom # if n <= 1, return
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j hanoi_recur
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hanoi_bottom:
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li $v0, 1 # return 1
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jr $ra
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hanoi_recur:
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subi $sp, $sp, 8 # move sp down by 2 word
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sw $s0, 4($sp) # first word is the n in caller
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sw $ra, 0($sp) # second word is the return addr of this callee
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move $s0, $a0
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subi $a0, $s0, 1
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jal hanoi
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sll $v0, $v0, 1 # hanoi(n - 1) * 2
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ori $v0, $v0, 1 # hanoi(n - 1) * 2 + 1
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lw $s0, 4($sp) # reverse s0
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lw $ra, 0($sp) # reverse ra
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addi $sp, $sp, 8
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jr $ra
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