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#ifndef _I386_BITOPS_H

#define _I386_BITOPS_H

/*

 * Copyright 1992, Linus Torvalds.

 */

/*

 * These have to be done with inline assembly: that way the bit-setting

 * is guaranteed to be atomic. All bit operations return 0 if the bit

 * was cleared before the operation and != 0 if it was not.

 *

 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).

 */

#ifdef __SMP__

#define LOCK_PREFIX "lock ; "

#define SMPVOL volatile

#else

#define LOCK_PREFIX ""

#define SMPVOL

#endif

/*

 * Some hacks to defeat gcc over-optimizations..

 */

struct __dummy { unsigned long a[100]; };

#define ADDR (*(struct __dummy *) addr)

#define CONST_ADDR (*(const struct __dummy *) addr)

extern __inline__ int set_bit(int nr, SMPVOL void * addr)

{

        int oldbit;

        __asm__ __volatile__(LOCK_PREFIX

                "btsl %2,%1\n\tsbbl %0,%0"

                :"=r" (oldbit),"=m" (ADDR)

                :"ir" (nr));

        return oldbit;

}

extern __inline__ int clear_bit(int nr, SMPVOL void * addr)

{

        int oldbit;

        __asm__ __volatile__(LOCK_PREFIX

                "btrl %2,%1\n\tsbbl %0,%0"

                :"=r" (oldbit),"=m" (ADDR)

                :"ir" (nr));

        return oldbit;

}

extern __inline__ int change_bit(int nr, SMPVOL void * addr)

{

        int oldbit;

        __asm__ __volatile__(LOCK_PREFIX

                "btcl %2,%1\n\tsbbl %0,%0"

                :"=r" (oldbit),"=m" (ADDR)

                :"ir" (nr));

        return oldbit;

}

/*

 * This routine doesn't need to be atomic.

 */

extern __inline__ int test_bit(int nr, const SMPVOL void * addr)

{

        return ((1UL << (nr & 31)) & (((const unsigned int *) addr)[nr >> 5])) != 0;

}

/*

 * Find-bit routines..

 */

extern __inline__ int find_first_zero_bit(void * addr, unsigned size)

{

        int res;

        if (!size)

                return 0;

        __asm__("cld\n\t"

                "movl $-1,%%eax\n\t"

                "xorl %%edx,%%edx\n\t"

                "repe; scasl\n\t"

                "je 1f\n\t"

                "xorl -4(%%edi),%%eax\n\t"

                "subl $4,%%edi\n\t"

                "bsfl %%eax,%%edx\n"

                "1:\tsubl %%ebx,%%edi\n\t"

                "shll $3,%%edi\n\t"

                "addl %%edi,%%edx"

                :"=d" (res)

                :"c" ((size + 31) >> 5), "D" (addr), "b" (addr)

                :"ax", "cx", "di");

        return res;

}

extern __inline__ int find_next_zero_bit (void * addr, int size, int offset)

{

        unsigned long * p = ((unsigned long *) addr) + (offset >> 5);

        int set = 0, bit = offset & 31, res;

        if (bit) {

                /*

                 * Look for zero in first byte

                 */

                __asm__("bsfl %1,%0\n\t"

                        "jne 1f\n\t"

                        "movl $32, %0\n"

                        "1:"

                        : "=r" (set)

                        : "r" (~(*p >> bit)));

                if (set < (32 - bit))

                        return set + offset;

                set = 32 - bit;

                p++;

        }

        /*

         * No zero yet, search remaining full bytes for a zero

         */

        res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr));

        return (offset + set + res);

}

/*

 * ffz = Find First Zero in word. Undefined if no zero exists,

 * so code should check against ~0UL first..

 */

extern __inline__ unsigned long ffz(unsigned long word)

{

        __asm__("bsfl %1,%0"

                :"=r" (word)

                :"r" (~word));

        return word;

}

#endif /* _I386_BITOPS_H */