x86: Fix ASM_X86__ header guards
[linux-2.6.git] / arch / x86 / include / asm / div64.h
1 #ifndef _ASM_X86_DIV64_H
2 #define _ASM_X86_DIV64_H
3
4 #ifdef CONFIG_X86_32
5
6 #include <linux/types.h>
7
8 /*
9  * do_div() is NOT a C function. It wants to return
10  * two values (the quotient and the remainder), but
11  * since that doesn't work very well in C, what it
12  * does is:
13  *
14  * - modifies the 64-bit dividend _in_place_
15  * - returns the 32-bit remainder
16  *
17  * This ends up being the most efficient "calling
18  * convention" on x86.
19  */
20 #define do_div(n, base)                                         \
21 ({                                                              \
22         unsigned long __upper, __low, __high, __mod, __base;    \
23         __base = (base);                                        \
24         asm("":"=a" (__low), "=d" (__high) : "A" (n));          \
25         __upper = __high;                                       \
26         if (__high) {                                           \
27                 __upper = __high % (__base);                    \
28                 __high = __high / (__base);                     \
29         }                                                       \
30         asm("divl %2":"=a" (__low), "=d" (__mod)                \
31             : "rm" (__base), "0" (__low), "1" (__upper));       \
32         asm("":"=A" (n) : "a" (__low), "d" (__high));           \
33         __mod;                                                  \
34 })
35
36 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
37 {
38         union {
39                 u64 v64;
40                 u32 v32[2];
41         } d = { dividend };
42         u32 upper;
43
44         upper = d.v32[1];
45         d.v32[1] = 0;
46         if (upper >= divisor) {
47                 d.v32[1] = upper / divisor;
48                 upper %= divisor;
49         }
50         asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) :
51                 "rm" (divisor), "0" (d.v32[0]), "1" (upper));
52         return d.v64;
53 }
54 #define div_u64_rem     div_u64_rem
55
56 #else
57 # include <asm-generic/div64.h>
58 #endif /* CONFIG_X86_32 */
59
60 #endif /* _ASM_X86_DIV64_H */