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/*
* Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
*
* Based on former do_div() implementation from asm-parisc/div64.h:
* Copyright (C) 1999 Hewlett-Packard Co
* Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
*
*
* 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.
*/
#include <linux/module.h>
#include <linux/math64.h>
/* 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);
#ifndef div_s64_rem
s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
{
u64 quotient;
if (dividend < 0) {
quotient = div_u64_rem(-dividend, abs(divisor), (u32 *)remainder);
*remainder = -*remainder;
if (divisor > 0)
quotient = -quotient;
} else {
quotient = div_u64_rem(dividend, abs(divisor), (u32 *)remainder);
if (divisor < 0)
quotient = -quotient;
}
return quotient;
}
EXPORT_SYMBOL(div_s64_rem);
#endif
/* 64bit divisor, dividend and result. dynamic precision */
#ifndef div64_u64
u64 div64_u64(u64 dividend, u64 divisor)
{
u32 high, d;
high = divisor >> 32;
if (high) {
unsigned int shift = fls(high);
d = divisor >> shift;
dividend >>= shift;
} else
d = divisor;
return div_u64(dividend, d);
}
EXPORT_SYMBOL(div64_u64);
#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)
{
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;
}
EXPORT_SYMBOL(iter_div_u64_rem);
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