ia64/linux-2.6.18-xen.hg

view include/asm-generic/div64.h @ 782:9ab1c319531f

merge with linux-2.6.18-xen.hg
author Isaku Yamahata <yamahata@valinux.co.jp>
date Wed Jan 28 13:07:23 2009 +0900 (2009-01-28)
parents 831230e53067
children
line source
1 #ifndef _ASM_GENERIC_DIV64_H
2 #define _ASM_GENERIC_DIV64_H
3 /*
4 * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
5 * Based on former asm-ppc/div64.h and asm-m68knommu/div64.h
6 *
7 * The semantics of do_div() are:
8 *
9 * uint32_t do_div(uint64_t *n, uint32_t base)
10 * {
11 * uint32_t remainder = *n % base;
12 * *n = *n / base;
13 * return remainder;
14 * }
15 *
16 * NOTE: macro parameter n is evaluated multiple times,
17 * beware of side effects!
18 */
20 #include <linux/types.h>
21 #include <linux/compiler.h>
23 #if BITS_PER_LONG == 64
25 # define do_div(n,base) ({ \
26 uint32_t __base = (base); \
27 uint32_t __rem; \
28 __rem = ((uint64_t)(n)) % __base; \
29 (n) = ((uint64_t)(n)) / __base; \
30 __rem; \
31 })
33 #elif BITS_PER_LONG == 32
35 extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
37 /* The unnecessary pointer compare is there
38 * to check for type safety (n must be 64bit)
39 */
40 # define do_div(n,base) ({ \
41 uint32_t __base = (base); \
42 uint32_t __rem; \
43 (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
44 if (likely(((n) >> 32) == 0)) { \
45 __rem = (uint32_t)(n) % __base; \
46 (n) = (uint32_t)(n) / __base; \
47 } else \
48 __rem = __div64_32(&(n), __base); \
49 __rem; \
50 })
52 #else /* BITS_PER_LONG == ?? */
54 # error do_div() does not yet support the C64
56 #endif /* BITS_PER_LONG */
58 #endif /* _ASM_GENERIC_DIV64_H */