diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-i386/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-i386/div64.h')
-rw-r--r-- | include/asm-i386/div64.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/include/asm-i386/div64.h b/include/asm-i386/div64.h new file mode 100644 index 000000000000..28ed8b296afc --- /dev/null +++ b/include/asm-i386/div64.h | |||
@@ -0,0 +1,48 @@ | |||
1 | #ifndef __I386_DIV64 | ||
2 | #define __I386_DIV64 | ||
3 | |||
4 | /* | ||
5 | * do_div() is NOT a C function. It wants to return | ||
6 | * two values (the quotient and the remainder), but | ||
7 | * since that doesn't work very well in C, what it | ||
8 | * does is: | ||
9 | * | ||
10 | * - modifies the 64-bit dividend _in_place_ | ||
11 | * - returns the 32-bit remainder | ||
12 | * | ||
13 | * This ends up being the most efficient "calling | ||
14 | * convention" on x86. | ||
15 | */ | ||
16 | #define do_div(n,base) ({ \ | ||
17 | unsigned long __upper, __low, __high, __mod, __base; \ | ||
18 | __base = (base); \ | ||
19 | asm("":"=a" (__low), "=d" (__high):"A" (n)); \ | ||
20 | __upper = __high; \ | ||
21 | if (__high) { \ | ||
22 | __upper = __high % (__base); \ | ||
23 | __high = __high / (__base); \ | ||
24 | } \ | ||
25 | asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \ | ||
26 | asm("":"=A" (n):"a" (__low),"d" (__high)); \ | ||
27 | __mod; \ | ||
28 | }) | ||
29 | |||
30 | /* | ||
31 | * (long)X = ((long long)divs) / (long)div | ||
32 | * (long)rem = ((long long)divs) % (long)div | ||
33 | * | ||
34 | * Warning, this will do an exception if X overflows. | ||
35 | */ | ||
36 | #define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c) | ||
37 | |||
38 | extern inline long | ||
39 | div_ll_X_l_rem(long long divs, long div, long *rem) | ||
40 | { | ||
41 | long dum2; | ||
42 | __asm__("divl %2":"=a"(dum2), "=d"(*rem) | ||
43 | : "rm"(div), "A"(divs)); | ||
44 | |||
45 | return dum2; | ||
46 | |||
47 | } | ||
48 | #endif | ||