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linux/include/asm-generic/div64.h
Stephen Hemminger 3927f2e8f9 [NET]: div64_64 consolidate (rev3)
Here is the current version of the 64 bit divide common code.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:23:33 -07:00

66 lines
1.5 KiB
C

#ifndef _ASM_GENERIC_DIV64_H
#define _ASM_GENERIC_DIV64_H
/*
* Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
* Based on former asm-ppc/div64.h and asm-m68knommu/div64.h
*
* The semantics of do_div() are:
*
* uint32_t do_div(uint64_t *n, uint32_t base)
* {
* uint32_t remainder = *n % base;
* *n = *n / base;
* return remainder;
* }
*
* NOTE: macro parameter n is evaluated multiple times,
* beware of side effects!
*/
#include <linux/types.h>
#include <linux/compiler.h>
#if BITS_PER_LONG == 64
# define do_div(n,base) ({ \
uint32_t __base = (base); \
uint32_t __rem; \
__rem = ((uint64_t)(n)) % __base; \
(n) = ((uint64_t)(n)) / __base; \
__rem; \
})
static inline uint64_t div64_64(uint64_t dividend, uint64_t divisor)
{
return dividend / divisor;
}
#elif BITS_PER_LONG == 32
extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
/* The unnecessary pointer compare is there
* to check for type safety (n must be 64bit)
*/
# define do_div(n,base) ({ \
uint32_t __base = (base); \
uint32_t __rem; \
(void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
if (likely(((n) >> 32) == 0)) { \
__rem = (uint32_t)(n) % __base; \
(n) = (uint32_t)(n) / __base; \
} else \
__rem = __div64_32(&(n), __base); \
__rem; \
})
extern uint64_t div64_64(uint64_t dividend, uint64_t divisor);
#else /* BITS_PER_LONG == ?? */
# error do_div() does not yet support the C64
#endif /* BITS_PER_LONG */
#endif /* _ASM_GENERIC_DIV64_H */