Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * 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/types.h>
#include <linux/module.h>
#include <asm/div64.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);
 
/* 64bit divisor, dividend and result. dynamic precision */
uint64_t div64_64(uint64_t dividend, uint64_t divisor)
{
	uint32_t high, d;
 
	high = divisor >> 32;
	if (high) {
		unsigned int shift = fls(high);
 
		d = divisor >> shift;
		dividend >>= shift;
	} else
		d = divisor;
 
	do_div(dividend, d);
 
	return dividend;
}
EXPORT_SYMBOL(div64_64);
 
#endif /* BITS_PER_LONG == 32 */