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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2009 Piotr Esden-Tempski <piotr@esden.net>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef LIBOPENCM3_TOOLS_H
#define LIBOPENCM3_TOOLS_H
/*
* Register accessors / manipulators
*/
/* Get register content. */
#define GET_REG(REG) ((uint16_t) *REG)
/* Set register content. */
#define SET_REG(REG, VAL) (*REG = (uint16_t)VAL)
/* Clear register bit. */
#define CLR_REG_BIT(REG, BIT) SET_REG(REG, (~BIT))
/* Clear register bit masking out some bits that must not be touched. */
#define CLR_REG_BIT_MSK(REG, MSK, BIT) \
SET_REG(REG, (GET_REG(REG) & MSK & (~BIT)))
/* Get masked out bit value. */
#define GET_REG_BIT(REG, BIT) (GET_REG(REG) & BIT)
/*
* Set/reset a bit in a masked window by using toggle mechanism.
*
* This means that we look at the bits in the bit window designated by
* the mask. If the bit in the masked window is not matching the
* bit mask BIT then we write 1 and if the bit in the masked window is
* matching the bit mask BIT we write 0.
*
* TODO: We may need a faster implementation of that one?
*/
#define TOG_SET_REG_BIT_MSK(REG, MSK, BIT) \
do { \
register uint16_t toggle_mask = GET_REG(REG) & (MSK); \
register uint16_t bit_selector; \
for (bit_selector = 1; bit_selector; bit_selector <<= 1) { \
if ((bit_selector & (BIT)) != 0) { \
toggle_mask ^= bit_selector; \
} \
} \
SET_REG(REG, toggle_mask); \
} while (0)
#endif
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