1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
#ifndef _ASM_X86_DIV64_H
#define _ASM_X86_DIV64_H
#ifdef CONFIG_X86_32
#include <linux/types.h>
/*
* do_div() is NOT a C function. It wants to return
* two values (the quotient and the remainder), but
* since that doesn't work very well in C, what it
* does is:
*
* - modifies the 64-bit dividend _in_place_
* - returns the 32-bit remainder
*
* This ends up being the most efficient "calling
* convention" on x86.
*/
#define do_div(n, base) \
({ \
unsigned long __upper, __low, __high, __mod, __base; \
__base = (base); \
asm("":"=a" (__low), "=d" (__high) : "A" (n)); \
__upper = __high; \
if (__high) { \
__upper = __high % (__base); \
__high = __high / (__base); \
} \
asm("divl %2":"=a" (__low), "=d" (__mod) \
: "rm" (__base), "0" (__low), "1" (__upper)); \
asm("":"=A" (n) : "a" (__low), "d" (__high)); \
__mod; \
})
/*
* (long)X = ((long long)divs) / (long)div
* (long)rem = ((long long)divs) % (long)div
*
* Warning, this will do an exception if X overflows.
*/
#define div_long_long_rem(a, b, c) div_ll_X_l_rem(a, b, c)
static inline long div_ll_X_l_rem(long long divs, long div, long *rem)
{
long dum2;
asm("divl %2":"=a"(dum2), "=d"(*rem)
: "rm"(div), "A"(divs));
return dum2;
}
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
union {
u64 v64;
u32 v32[2];
} d = { dividend };
u32 upper;
upper = d.v32[1];
d.v32[1] = 0;
if (upper >= divisor) {
d.v32[1] = upper / divisor;
upper %= divisor;
}
asm ("divl %2" : "=a" (d.v32[0]), "=d" (*remainder) :
"rm" (divisor), "0" (d.v32[0]), "1" (upper));
return d.v64;
}
#define div_u64_rem div_u64_rem
extern uint64_t div64_64(uint64_t dividend, uint64_t divisor);
#else
# include <asm-generic/div64.h>
#endif /* CONFIG_X86_32 */
#endif /* _ASM_X86_DIV64_H */
|
