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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef __I386_DIV64
2#define __I386_DIV64
3
Stephen Hemminger3927f2e2007-03-25 19:54:23 -07004#include <linux/types.h>
5
Linus Torvalds1da177e2005-04-16 15:20:36 -07006/*
7 * do_div() is NOT a C function. It wants to return
8 * two values (the quotient and the remainder), but
9 * since that doesn't work very well in C, what it
10 * does is:
11 *
12 * - modifies the 64-bit dividend _in_place_
13 * - returns the 32-bit remainder
14 *
15 * This ends up being the most efficient "calling
16 * convention" on x86.
17 */
18#define do_div(n,base) ({ \
19 unsigned long __upper, __low, __high, __mod, __base; \
20 __base = (base); \
21 asm("":"=a" (__low), "=d" (__high):"A" (n)); \
22 __upper = __high; \
23 if (__high) { \
24 __upper = __high % (__base); \
25 __high = __high / (__base); \
26 } \
27 asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \
28 asm("":"=A" (n):"a" (__low),"d" (__high)); \
29 __mod; \
30})
31
32/*
33 * (long)X = ((long long)divs) / (long)div
34 * (long)rem = ((long long)divs) % (long)div
35 *
36 * Warning, this will do an exception if X overflows.
37 */
38#define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c)
39
Adrian Bunke2afe67452005-09-10 00:27:16 -070040static inline long
Linus Torvalds1da177e2005-04-16 15:20:36 -070041div_ll_X_l_rem(long long divs, long div, long *rem)
42{
43 long dum2;
44 __asm__("divl %2":"=a"(dum2), "=d"(*rem)
45 : "rm"(div), "A"(divs));
46
47 return dum2;
48
49}
Stephen Hemminger3927f2e2007-03-25 19:54:23 -070050
51extern uint64_t div64_64(uint64_t dividend, uint64_t divisor);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052#endif