math64.h

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#ifndef _LINUX_MATH64_H
#define _LINUX_MATH64_H

#include <linux/types.h>
#include <asm/div64.h>

#if BITS_PER_LONG == 64

#define div64_long(x,y) div64_s64((x),(y))

static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
    *remainder = dividend % divisor;
    return dividend / divisor;
}

static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
{
    *remainder = dividend % divisor;
    return dividend / divisor;
}

static inline u64 div64_u64(u64 dividend, u64 divisor)
{
    return dividend / divisor;
}

static inline s64 div64_s64(s64 dividend, s64 divisor)
{
    return dividend / divisor;
}

#elif BITS_PER_LONG == 32

#define div64_long(x,y) div_s64((x),(y))

#ifndef div_u64_rem
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
    *remainder = do_div(dividend, divisor);
    return dividend;
}
#endif

#ifndef div_s64_rem
extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
#endif

#ifndef div64_u64
extern u64 div64_u64(u64 dividend, u64 divisor);
#endif

#ifndef div64_s64
extern s64 div64_s64(s64 dividend, s64 divisor);
#endif

#endif /* BITS_PER_LONG */

#ifndef div_u64
static inline u64 div_u64(u64 dividend, u32 divisor)
{
    u32 remainder;
    return div_u64_rem(dividend, divisor, &remainder);
}
#endif

#ifndef div_s64
static inline s64 div_s64(s64 dividend, s32 divisor)
{
    s32 remainder;
    return div_s64_rem(dividend, divisor, &remainder);
}
#endif

u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);

static __always_inline u32
__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
{
    u32 ret = 0;

    while (dividend >= divisor) {
        /* The following asm() prevents the compiler from
           optimising this loop into a modulo operation.  */
        asm("" : "+rm"(dividend));

        dividend -= divisor;
        ret++;
    }

    *remainder = dividend;

    return ret;
}

#endif /* _LINUX_MATH64_H */