apple2js/js/cards/thunderclock.js

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/* Copyright 2010-2019 Will Scullin <scullin@scullinsteel.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
import { debug, toHex } from '../util';
import { rom } from '../roms/cards/thunderclock';
export default function Thunderclock()
{
var LOC = {
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CONTROL: 0x80,
AUX: 0x88
};
var COMMANDS = {
MASK: 0x18,
REGHOLD: 0x00,
REGSHIFT: 0x08,
TIMED: 0x18
};
var FLAGS = {
DATA: 0x01,
CLOCK: 0x02,
STROBE: 0x04
};
function _init() {
debug('Thunderclock');
}
var _clock = false;
var _strobe = false;
var _shiftMode = false;
var _register = 0;
var _bits = [];
var _command = COMMANDS.HOLD;
function _debug() {
// debug.apply(this, arguments);
}
function _calcBits() {
function shift(val) {
for (var idx = 0; idx < 4; idx++) {
_bits.push((val & 0x08) !== 0);
val <<= 1;
}
}
function shiftBCD(val) {
shift(parseInt(val / 10, 10));
shift(parseInt(val % 10, 10));
}
var now = new Date();
var day = now.getDate();
var weekday = now.getDay();
var month = now.getMonth() + 1;
var hour = now.getHours();
var minutes = now.getMinutes();
var seconds = now.getSeconds();
_bits = [];
shift(month);
shift(weekday);
shiftBCD(day);
shiftBCD(hour);
shiftBCD(minutes);
shiftBCD(seconds);
}
function _shift() {
if (_shiftMode) {
if (_bits.pop()) {
_debug('shifting 1');
_register |= 0x80;
} else {
_debug('shifting 0');
_register &= 0x7f;
}
}
}
function _access(off, val) {
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switch (off & 0x8F) {
case LOC.CONTROL:
if (val !== undefined) {
var strobe = val & FLAGS.STROBE ? true : false;
if (strobe !== _strobe) {
_debug('strobe', _strobe ? 'high' : 'low');
if (strobe) {
_command = val & COMMANDS.MASK;
switch (_command) {
case COMMANDS.TIMED:
_debug('TIMED');
_calcBits();
break;
case COMMANDS.REGSHIFT:
_debug('REGSHIFT');
_shiftMode = true;
_shift();
break;
case COMMANDS.REGHOLD:
_debug('REGHOLD');
_shiftMode = false;
break;
default:
_debug('Unknown command', toHex(_command));
}
}
}
var clock = val & FLAGS.CLOCK ? true : false;
if (clock !== _clock) {
_clock = clock;
_debug('clock', _clock ? 'high' : 'low');
if (clock) {
_shift();
}
}
}
break;
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case LOC.AUX:
break;
}
return _register;
}
_init();
return {
read: function thunderclock_read(page, off) {
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var result;
if (page < 0xc8) {
result = rom[off];
} else {
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result = rom[(page - 0xc8) << 8 | off];
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}
return result;
},
write: function thunderclock_write() {
},
ioSwitch: function thunderclock_ioSwitch(off, val) {
return _access(off, val);
}
};
}