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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-generic/div64.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-generic/div64.h')
-rw-r--r--include/asm-generic/div64.h58
1 files changed, 58 insertions, 0 deletions
diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
new file mode 100644
index 000000000000..8f4e3193342e
--- /dev/null
+++ b/include/asm-generic/div64.h
@@ -0,0 +1,58 @@
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 */
19
20#include <linux/types.h>
21#include <linux/compiler.h>
22
23#if BITS_PER_LONG == 64
24
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 })
32
33#elif BITS_PER_LONG == 32
34
35extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
36
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 })
51
52#else /* BITS_PER_LONG == ?? */
53
54# error do_div() does not yet support the C64
55
56#endif /* BITS_PER_LONG */
57
58#endif /* _ASM_GENERIC_DIV64_H */