From a000308104aab27c2dde9a306f1bc654b2db4806 Mon Sep 17 00:00:00 2001 From: Yuchen Pei Date: Wed, 29 Nov 2017 12:30:41 +0100 Subject: first commit --- projects/08/FunctionCalls/FibonacciElement/Main.vm | 30 ++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 projects/08/FunctionCalls/FibonacciElement/Main.vm (limited to 'projects/08/FunctionCalls/FibonacciElement/Main.vm') diff --git a/projects/08/FunctionCalls/FibonacciElement/Main.vm b/projects/08/FunctionCalls/FibonacciElement/Main.vm new file mode 100644 index 0000000..55e5ad2 --- /dev/null +++ b/projects/08/FunctionCalls/FibonacciElement/Main.vm @@ -0,0 +1,30 @@ +// This file is part of www.nand2tetris.org +// and the book "The Elements of Computing Systems" +// by Nisan and Schocken, MIT Press. +// File name: projects/08/FunctionCalls/FibonacciElement/Main.vm + +// Computes the n'th element of the Fibonacci series, recursively. +// n is given in argument[0]. Called by the Sys.init function +// (part of the Sys.vm file), which also pushes the argument[0] +// parameter before this code starts running. + +function Main.fibonacci 0 +push argument 0 +push constant 2 +lt // checks if n<2 +if-goto IF_TRUE +goto IF_FALSE +label IF_TRUE // if n<2, return n +push argument 0 +return +label IF_FALSE // if n>=2, returns fib(n-2)+fib(n-1) +push argument 0 +push constant 2 +sub +call Main.fibonacci 1 // computes fib(n-2) +push argument 0 +push constant 1 +sub +call Main.fibonacci 1 // computes fib(n-1) +add // returns fib(n-1) + fib(n-2) +return -- cgit v1.2.3