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/*

 * Copyright (C) 2003 Bernardo Innocenti 

 *

 * Based on former do_div() implementation from asm-parisc/div64.h:

 *	Copyright (C) 1999 Hewlett-Packard Co

 *	Copyright (C) 1999 David Mosberger-Tang 

 *

 *

 * Generic C version of 64bit/32bit division and modulo, with

 * 64bit result and 32bit remainder.

 *

 * The fast case for (n>>32 == 0) is handled inline by do_div(). 

 *

 * Code generated for this function might be very inefficient

 * for some CPUs. __div64_32() can be overridden by linking arch-specific

 * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.

 */

/* Not needed on 64bit architectures */

#if BITS_PER_LONG == 32

uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base)

{

	uint64_t rem = *n;

	uint64_t b = base;

	uint64_t res, d = 1;

	uint32_t high = rem >> 32;

	/* Reduce the thing a bit first */

	res = 0;

	if (high >= base) {

		high /= base;

		res = (uint64_t) high << 32;

		rem -= (uint64_t) (high*base) << 32;

	}

	while ((int64_t)b > 0 && b < rem) {

		b = b+b;

		d = d+d;

	}

	do {

		if (rem >= b) {

			rem -= b;

			res += d;

		}

		b >>= 1;

		d >>= 1;

	} while (d);

	*n = res;

	return rem;

}

EXPORT_SYMBOL(__div64_32);

EXPORT_SYMBOL(div_s64_rem);

#endif

/**

 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder

 * @dividend:	64bit dividend

 * @divisor:	64bit divisor

 * @remainder:  64bit remainder

 *

 * This implementation is a comparable to algorithm used by div64_u64.

 * But this operation, which includes math for calculating the remainder,

 * is kept distinct to avoid slowing down the div64_u64 operation on 32bit

 * systems.

 */

#ifndef div64_u64_rem

u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)

{

	u32 high = divisor >> 32;

	u64 quot;

	if (high == 0) {

		u32 rem32;

		quot = div_u64_rem(dividend, divisor, &rem32);

		*remainder = rem32;

	} else {

		int n = 1 + fls(high);

		quot = div_u64(dividend >> n, divisor >> n);

		if (quot != 0)

			quot--;

		*remainder = dividend - quot * divisor;

		if (*remainder >= divisor) {

			quot++;

			*remainder -= divisor;

		}

	}

	return quot;

}

EXPORT_SYMBOL(div64_u64_rem);

#endif

/**

 * div64_u64 - unsigned 64bit divide with 64bit divisor

 * @dividend:	64bit dividend

 * @divisor:	64bit divisor

 *

 * This implementation is a modified version of the algorithm proposed

 * by the book 'Hacker's Delight'.  The original source and full proof

 * can be found here and is available for use without restriction.

 *

 * 'http://www.hackersdelight.org/hdcodetxt/divDouble.c.txt'

 */

#ifndef div64_u64

u64 div64_u64(u64 dividend, u64 divisor)

{

	u32 high = divisor >> 32;

	u64 quot;

	if (high == 0) {

		quot = div_u64(dividend, divisor);

	} else {

		int n = 1 + fls(high);

		quot = div_u64(dividend >> n, divisor >> n);

		if (quot != 0)

			quot--;

		if ((dividend - quot * divisor) >= divisor)

			quot++;

	}

	return quot;

}

EXPORT_SYMBOL(div64_u64);

#endif

/**

 * div64_s64 - signed 64bit divide with 64bit divisor

 * @dividend:	64bit dividend

 * @divisor:	64bit divisor

 */

#ifndef div64_s64

s64 div64_s64(s64 dividend, s64 divisor)

{

	s64 quot, t;

	quot = div64_u64(abs(dividend), abs(divisor));

	t = (dividend ^ divisor) >> 63;

	return (quot ^ t) - t;

}

EXPORT_SYMBOL(div64_s64);

#endif

#endif /* BITS_PER_LONG == 32 */

/*

 * Iterative div/mod for use when dividend is not expected to be much

 * bigger than divisor.

 */

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

{

	return __iter_div_u64_rem(dividend, divisor, remainder);

}