53 lines
1.3 KiB
Plaintext
53 lines
1.3 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/12/Sys.jack
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/**
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* A library that supports various program execution services.
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*/
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class Sys {
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/** Performs all the initializations required by the OS. */
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function void init() {
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do Math.init();
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do Memory.init();
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do Screen.init();
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do Keyboard.init();
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do Output.init();
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do Main.main();
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do Sys.halt();
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return;
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}
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/** Halts the program execution. */
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function void halt() {
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while (true) {}
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return;
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}
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/** Waits approximately duration milliseconds and returns. */
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function void wait(int duration) {
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var int i, j;
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let i = 0;
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while (i < duration) {
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let i = i + 1;
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let j = 0;
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while (j < 50) {
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let j = j + 1;
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}
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}
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return;
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}
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/** Displays the given error code in the form "ERR<errorCode>",
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* and halts the program's execution. */
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function void error(int errorCode) {
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do Output.printString("ERR<");
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do Output.printInt(errorCode);
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do Output.printString(">");
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do Sys.halt();
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return;
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}
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}
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