50 lines
1.2 KiB
Plaintext
50 lines
1.2 KiB
Plaintext
// This file is part of www.nand2tetris.org
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// and the book "The Elements of Computing Systems"
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// by Nisan and Schocken, MIT Press.
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// File name: projects/08/ProgramFlow/FibonacciSeries/FibonacciSeries.vm
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// Puts the first argument[0] elements of the Fibonacci series
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// in the memory, starting in the address given in argument[1].
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// Argument[0] and argument[1] are initialized by the test script
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// before this code starts running.
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push argument 1
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pop pointer 1 // that = argument[1]
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push constant 0
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pop that 0 // first element in the series = 0
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push constant 1
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pop that 1 // second element in the series = 1
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push argument 0
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push constant 2
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sub
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pop argument 0 // num_of_elements -= 2 (first 2 elements are set)
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label MAIN_LOOP_START
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push argument 0
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if-goto COMPUTE_ELEMENT // if num_of_elements > 0, goto COMPUTE_ELEMENT
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goto END_PROGRAM // otherwise, goto END_PROGRAM
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label COMPUTE_ELEMENT
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push that 0
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push that 1
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add
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pop that 2 // that[2] = that[0] + that[1]
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push pointer 1
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push constant 1
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add
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pop pointer 1 // that += 1
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push argument 0
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push constant 1
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sub
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pop argument 0 // num_of_elements--
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goto MAIN_LOOP_START
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label END_PROGRAM
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