57 lines
1.5 KiB
JavaScript
57 lines
1.5 KiB
JavaScript
/*
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* 6502 Based Virtual Computer
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* Copyright (C) 2011 Scott C. Duensing <scott@jaegertech.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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// Our Clock object.
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function clock() {
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// --- Private variables.
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// Memory location for PRNG value.
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var MEMORY = null;
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var MEMORY_START = 0;
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var CLOCK_ADDRESS = 0;
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// Clock values.
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var MILLISECONDS = 0;
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var CLOCK = 0;
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// --- Private methods.
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var clockTick = function() {
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MEMORY.writeByte(CLOCK_ADDRESS, CLOCK++);
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if (CLOCK > 255) CLOCK = 0;
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setTimeout(function(){
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clockTick();
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}, MILLISECONDS);
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};
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// --- Public methods.
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// Attach clock to DOM.
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this.attach = function(newMemory, newStartPosition, newMilliseconds) {
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MEMORY = newMemory;
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MEMORY_START = newStartPosition;
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CLOCK_ADDRESS = MEMORY_START;
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MILLISECONDS = newMilliseconds;
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clockTick();
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};
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}
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