/**
 * Helper functions for bit arithmetic
 *
 * Copyright (C) 2013 Freie Universität Berlin
 *
 * This file subject to the terms and conditions of the GNU Lesser General
 * Public License. See the file LICENSE in the top level directory for more
 * details.
 *
 * @defgroup bitarithm Bit Arithmetic
 * @ingroup	lib
 * @{
 * @file
 * @author Freie Universität Berlin, Computer Systems & Telematics
 * @author Kaspar Schleiser <kaspar.schleiser@fu-berlin.de>
 */

#ifndef BITARITHM_H_
#define BITARITHM_H_

#define BS(val, bit)		((val) & (bit))
#define BS_COND(condition, target, mask)		(target) ^= ( (-(condition) ^ (target)) & (mask) )
#define SETBIT(val, bit)	val |= (bit)
#define CLRBIT(val, bit)	val &= (~(bit))

/**
 * @name	Single Bit Defines
 * @{
 */
#ifndef BIT0
#define BIT0  0x00000001
#define BIT1  0x00000002
#define BIT2  0x00000004
#define BIT3  0x00000008
#define BIT4  0x00000010
#define BIT5  0x00000020
#define BIT6  0x00000040
#define BIT7  0x00000080
#define BIT8  0x00000100
#define BIT9  0x00000200
#define BIT10 0x00000400
#define BIT11 0x00000800
#define BIT12 0x00001000
#define BIT13 0x00002000
#define BIT14 0x00004000
#define BIT15 0x00008000
#endif
#ifndef BIT16
#define BIT16 0x00010000
#define BIT17 0x00020000
#define BIT18 0x00040000
#define BIT19 0x00080000
#define BIT20 0x00100000
#define BIT21 0x00200000
#define BIT22 0x00400000
#define BIT23 0x00800000
#define BIT24 0x01000000
#define BIT25 0x02000000
#define BIT26 0x04000000
#define BIT27 0x08000000
#define BIT28 0x10000000
#define BIT29 0x20000000
#define BIT30 0x40000000
#define BIT31 0x80000000
#endif
/** @} */

#define ARCH_32_BIT   (__INT_MAX__ == 2147483647)

/**
 * @brief	Returns the number of the highest '1' bit in a value
 * @param[in]	v	Input value
 * @return			Bit Number
 *
 * Source: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
 */
unsigned number_of_highest_bit(unsigned v);

/**
 * @brief	Returns the number of the lowest '1' bit in a value
 * @param[in]	v	Input value - must be unequal to '0', otherwise the
 *                  function will produce an infinite loop
 * @return			Bit Number
 *
 * Source: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
 */
unsigned number_of_lowest_bit(register unsigned v);

/**
 * @brief	Returns the number of bits set in a value
 * @param[in]	v	Input value
 * @return			Number of set bits
 *
 * Source: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogObvious
 */
unsigned number_of_bits_set(unsigned v);

/**
 * @}
 */

#endif /* BITARITHM_H_ */