You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
kamailio/bit_test.h

122 lines
3.3 KiB

/*
* $Id$
*
* Copyright (C) 2010 iptelorg GmbH
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* History
* -------
* 2010-04-26 Initial version (Miklos)
*/
/* Bit test functions:
* - int bit_test(int offset, unsigned int *addr)
* Returns the bit found at offset position
* in a bitstring pointed by addr.
*
* - int bit_test_and_set(int offset, unsigned int *addr)
* Returns the bit found at offset position
* in a bitstring pointed by addr, and sets
* the bit at the given offset.
*
* Note that 0 <= offset <= 128, Make sure that addr points to
* a large enough memory area.
*/
#ifndef _BIT_TEST_H
#define _BIT_TEST_H
/* fix __CPU_i386 -> __CPU_x86 */
#if defined __CPU_i386 && ! defined __CPU_x86
#define __CPU_x86
#endif
#ifdef CC_GCC_LIKE_ASM
#if defined __CPU_x86 || defined __CPU_x86_64
#define BIT_TEST_ASM
#endif
#endif
#ifdef BIT_TEST_ASM
/* Returns the bit found at offset position in the bitstring
* pointed by addr.
* Note that the CPU can access 4 bytes starting from addr,
* hence 0 <= offset < 128 holds. Make sure that addr points
* to a memory area that is large enough.
*/
static inline int bit_test(int offset, unsigned int *addr)
{
unsigned char v;
asm volatile(
" bt %2, %1 \n\t"
" setc %0 \n\t"
: "=qm" (v) : "m" (*addr), "r" (offset)
);
return (int)v;
}
/* Returns the bit found at offset position in the bitstring
* pointed by addr and sets it to 1.
* Note that the CPU can access 4 bytes starting from addr,
* hence 0 <= offset < 128 holds. Make sure that addr points
* to a memory area that is large enough.
*/
static inline int bit_test_and_set(int offset, unsigned int *addr)
{
unsigned char v;
asm volatile(
" bts %2, %1 \n\t"
" setc %0 \n\t"
: "=qm" (v) : "m" (*addr), "r" (offset)
);
return (int)v;
}
#else /* BIT_TEST_ASM */
/* Returns the bit found at offset position in the bitstring
* pointed by addr.
* Note that offset can be grater than 32, make sure that addr points
* to a memory area that is large enough.
*/
static inline int bit_test(int offset, unsigned int *addr)
{
return ((*(addr + offset/32)) & (1U << (offset % 32))) ? 1 : 0;
}
/* Returns the bit found at offset position in the bitstring
* pointed by addr and sets it to 1.
* Note that offset can be grater than 32, make sure that addr points
* to a memory area that is large enough.
*/
static inline int bit_test_and_set(int offset, unsigned int *addr)
{
unsigned int *i;
int mask, res;
i = addr + offset/32;
mask = 1U << (offset % 32);
res = ((*i) & mask) ? 1 : 0;
(*i) |= mask;
return res;
}
#endif /* BIT_TEST_ASM */
#endif /* #ifndef _BIT_TEST_H */