From d3a0cc3a8ba6dfeb64d3faeffdeb6845b60e5840 Mon Sep 17 00:00:00 2001
From: Yuchen Pei <me@ypei.me>
Date: Sat, 20 Jan 2018 15:41:49 +0100
Subject: rearranged the dir for github

- removed tools and pdfs
- rearranged the projects dirs
- added md files
- other minor changes
---
 projects/12/ScreenTest/Math.jack | 158 ---------------------------------------
 1 file changed, 158 deletions(-)
 delete mode 100644 projects/12/ScreenTest/Math.jack

(limited to 'projects/12/ScreenTest/Math.jack')

diff --git a/projects/12/ScreenTest/Math.jack b/projects/12/ScreenTest/Math.jack
deleted file mode 100644
index 01bce8f..0000000
--- a/projects/12/ScreenTest/Math.jack
+++ /dev/null
@@ -1,158 +0,0 @@
-// 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/12/Math.jack
-
-/**
- * A library of commonly used mathematical functions.
- * Note: Jack compilers implement multiplication and division using OS method calls.
- */
-class Math {
-    static Array twoToThe;
-
-    /** Initializes the library. */
-    function void init() {
-        var int i, x;
-        let x = 1;
-        let i = 0;
-        let twoToThe = Array.new(16);
-        while (i < 16){
-            let twoToThe[i] = x;
-            let x = x + x;
-            let i = i + 1;
-        }
-        return;
-    }
-
-    function boolean bit(int x, int i) {
-        return ~(x & twoToThe[i] = 0);
-    }
-
-    function int sign(int x) {
-        if (x > 0) {
-            return 1;
-        } else {
-            if (x < 0) {
-                return -1;
-            } else {
-                return 0;
-            }
-        }
-    }
-
-    /** Returns the absolute value of x. */
-    function int abs(int x) {
-        if (x > 0){
-            return x;
-        } else {
-            return -x;
-        }
-    }
-
-    /** Returns the product of x and y. 
-     *  When a Jack compiler detects the multiplication operator '*' in the 
-     *  program's code, it handles it by invoking this method. In other words,
-     *  the Jack expressions x*y and multiply(x,y) return the same value.
-     */
-    function int multiply(int x, int y) {
-        var int res, shiftedX, i;
-        let shiftedX = x;
-        let i = 0;
-        let res = 0;
-        //while ((~(twoToThe[i] > y)) & (i < 16)) {
-        while (i < 16) {
-            if (Math.bit(y, i)){
-                let res = res + shiftedX;
-            }
-            let shiftedX = shiftedX + shiftedX;
-            let i = i + 1;
-        }
-        return res;
-    }
-
-    /** Returns the integer part of x/y.
-     *  When a Jack compiler detects the multiplication operator '/' in the 
-     *  program's code, it handles it by invoking this method. In other words,
-     *  the Jack expressions x/y and divide(x,y) return the same value.
-     */
-    function int divide(int x, int y) {
-        var int ax, ay;
-        if (x > 0) {
-            if (y > 0) {
-                return Math.divide1(x, y);
-            } else {
-                return -Math.divide1(x, -y);
-            }
-        } else {
-            if (y > 0) {
-                return -Math.divide1(-x, y);
-            } else {
-                return Math.divide1(-x, -y);
-            }
-        }
-    }
-
-    function int divide1(int x, int y) {
-        var int q;
-        if (y = 0) {
-            do Output.printString("Error: division by zero.");
-            do Sys.error(0);
-        }
-        if ((y > x) | (y < 0)) {
-            return 0;
-        }
-        let q = Math.divide1(x, y * 2);
-        if (x - (2 * q * y) < y) {
-            return 2 * q;
-        } else {
-            return 2 * q + 1;
-        }
-    }
-
-    function int length(int x){
-        var int n;
-        let n = 14;
-        while (twoToThe[n] > x){
-            let n = n - 1;
-        }
-        return n;
-    }
-
-    /** Returns the integer part of the square root of x. */
-    function int sqrt(int x) {
-        var int y, k, z, w;
-        if (x < 0) {
-            do Output.printString("Error: square rooting a negative number.");
-            do Sys.error(0);
-        }
-        let k = Math.length(x) / 2;
-        let y = 0;
-        while (~(k < 0)) {
-            let z = y + twoToThe[k];
-            let w = z * z;
-            if ((~(w > x)) & (w > 0)) {
-                let y = z;
-            }
-            let k = k - 1;
-        }
-        return y;
-    }
-
-    /** Returns the greater number. */
-    function int max(int a, int b) {
-        if (a > b) {
-            return a;
-        } else {
-            return b;
-        }
-    }
-
-    /** Returns the smaller number. */
-    function int min(int a, int b) {
-        if (a < b) {
-            return a;
-        } else {
-            return b;
-        }
-    }
-}
-- 
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