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/*
 * This file is part of the libopenstm32 project.
 *
 * Copyright (C) 2009 Piotr Esden-Tempski <piotr@esden.net>
 *
 * 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef LIBOPENSTM32_TOOLS_H
#define LIBOPENSTM32_TOOLS_H

/******************************************************************************
 * Register accessors / manipulators
 ******************************************************************************/

/* Get register content */
#define GET_REG(REG) ((u16) *REG)
/* Set register content */
#define SET_REG(REG, VAL) (*REG = (u16)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
 * bitmask BIT then we write 1 and if the bit in the masked window is
 * matching the bitmask BIT we write 0.
 *
 * TODO: we may need a faster implementation of that one?
 */
#define TOG_SET_REG_BIT_MSK(REG, MSK, BIT) {                            \
        register u16 toggle_mask = GET_REG(REG) & MSK;                  \
        register u16 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);                                      \
    }

#endif /* LIBOPENSTM32_TOOLS_H */