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