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/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "encoder.hpp"
#include "utility.hpp"
static const int8_t transition_map[] = {
0, // 0000: noop
0, // 0001: start
0, // 0010: start
0, // 0011: rate
1, // 0100: end
0, // 0101: noop
0, // 0110: rate
-1, // 0111: end
-1, // 1000: end
0, // 1001: rate
0, // 1010: noop
1, // 1011: end
0, // 1100: rate
0, // 1101: start
0, // 1110: start
0, // 1111: noop
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};
int_fast8_t Encoder::update(
const uint_fast8_t phase_0,
const uint_fast8_t phase_1) {
state <<= 1;
state |= phase_0;
state <<= 1;
state |= phase_1;
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return transition_map[state & 0xf];
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}