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77ef50a5 VN |
1 | #ifndef ASM_X86__DIV64_H |
2 | #define ASM_X86__DIV64_H | |
428c5a23 | 3 | |
96a388de | 4 | #ifdef CONFIG_X86_32 |
428c5a23 CS |
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 | */ | |
925a09b2 JP |
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; \ | |
428c5a23 CS |
34 | }) |
35 | ||
2418f4f2 RZ |
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 | ||
96a388de | 56 | #else |
428c5a23 CS |
57 | # include <asm-generic/div64.h> |
58 | #endif /* CONFIG_X86_32 */ | |
59 | ||
77ef50a5 | 60 | #endif /* ASM_X86__DIV64_H */ |