tools.h

Go to the documentation of this file.

/*
 * 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_AND_SET(REG, MSK, BIT, EXTRA_BITS) \
        SET_REG((REG), (GET_REG((REG)) & (MSK) & (~(BIT))) | (EXTRA_BITS))
 
#define CLR_REG_BIT_MSK(REG, MSK, BIT) \
                CLR_REG_BIT_MSK_AND_SET((REG), (MSK), (BIT), 0)
 
/* 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_AND_SET(REG, MSK, BIT, EXTRA_BITS)          \
do {                                                                    \
        register uint16_t toggle_mask = GET_REG(REG) & (MSK);           \
        toggle_mask ^= BIT;                                             \
        SET_REG((REG), toggle_mask | (EXTRA_BITS));                     \
} while (0)
 
#define TOG_SET_REG_BIT_MSK(REG, MSK, BIT) \
        TOG_SET_REG_BIT_MSK_AND_SET((REG), (MSK), (BIT), 0)
 
#endif