drm/i915: acpi/video.c fix section mismatch warning
[linux-2.6/linux-acpi-2.6.git] / lib / div64.c
bloba111eb8de9cfeefb2bc82011ef580f970091bfcd
1 /*
2 * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
4 * Based on former do_div() implementation from asm-parisc/div64.h:
5 * Copyright (C) 1999 Hewlett-Packard Co
6 * Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
9 * Generic C version of 64bit/32bit division and modulo, with
10 * 64bit result and 32bit remainder.
12 * The fast case for (n>>32 == 0) is handled inline by do_div().
14 * Code generated for this function might be very inefficient
15 * for some CPUs. __div64_32() can be overridden by linking arch-specific
16 * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.
19 #include <linux/module.h>
20 #include <linux/math64.h>
22 /* Not needed on 64bit architectures */
23 #if BITS_PER_LONG == 32
25 uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base)
27 uint64_t rem = *n;
28 uint64_t b = base;
29 uint64_t res, d = 1;
30 uint32_t high = rem >> 32;
32 /* Reduce the thing a bit first */
33 res = 0;
34 if (high >= base) {
35 high /= base;
36 res = (uint64_t) high << 32;
37 rem -= (uint64_t) (high*base) << 32;
40 while ((int64_t)b > 0 && b < rem) {
41 b = b+b;
42 d = d+d;
45 do {
46 if (rem >= b) {
47 rem -= b;
48 res += d;
50 b >>= 1;
51 d >>= 1;
52 } while (d);
54 *n = res;
55 return rem;
58 EXPORT_SYMBOL(__div64_32);
60 #ifndef div_s64_rem
61 s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
63 u64 quotient;
65 if (dividend < 0) {
66 quotient = div_u64_rem(-dividend, abs(divisor), (u32 *)remainder);
67 *remainder = -*remainder;
68 if (divisor > 0)
69 quotient = -quotient;
70 } else {
71 quotient = div_u64_rem(dividend, abs(divisor), (u32 *)remainder);
72 if (divisor < 0)
73 quotient = -quotient;
75 return quotient;
77 EXPORT_SYMBOL(div_s64_rem);
78 #endif
80 /* 64bit divisor, dividend and result. dynamic precision */
81 #ifndef div64_u64
82 u64 div64_u64(u64 dividend, u64 divisor)
84 u32 high, d;
86 high = divisor >> 32;
87 if (high) {
88 unsigned int shift = fls(high);
90 d = divisor >> shift;
91 dividend >>= shift;
92 } else
93 d = divisor;
95 return div_u64(dividend, d);
97 EXPORT_SYMBOL(div64_u64);
98 #endif
100 #endif /* BITS_PER_LONG == 32 */
103 * Iterative div/mod for use when dividend is not expected to be much
104 * bigger than divisor.
106 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
108 return __iter_div_u64_rem(dividend, divisor, remainder);
110 EXPORT_SYMBOL(iter_div_u64_rem);