diff options
author | Peng Fan <peng.fan@nxp.com> | 2017-04-10 13:39:48 +0800 |
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committer | Tom Rini <trini@konsulko.com> | 2017-04-13 09:41:10 -0400 |
commit | 0342e335ba887817ed401e77be324e064ea7031e (patch) | |
tree | c9f5a342e8f21a2fa5e25fead03376f0e10742ff /lib/div64.c | |
parent | 6823e6fe66ad9e9043ca8a0da2d79f1d11af1f34 (diff) |
lib: div64: sync with Linux
Sync with Linux commit ad0376eb1483b ("Merge tag 'edac_for_4.11_2'").
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Tom Rini <trini@konsulko.com>
Diffstat (limited to 'lib/div64.c')
-rw-r--r-- | lib/div64.c | 141 |
1 files changed, 136 insertions, 5 deletions
diff --git a/lib/div64.c b/lib/div64.c index 319fca50fa7..206f582ca96 100644 --- a/lib/div64.c +++ b/lib/div64.c @@ -13,14 +13,19 @@ * * Code generated for this function might be very inefficient * for some CPUs. __div64_32() can be overridden by linking arch-specific - * assembly versions such as arch/powerpc/lib/div64.S and arch/sh/lib/div64.S. + * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S + * or by defining a preprocessor macro in arch/include/asm/div64.h. */ -#include <div64.h> -#include <linux/types.h> -#include <linux/compiler.h> +#include <linux/compat.h> +#include <linux/kernel.h> +#include <linux/math64.h> -uint32_t notrace __div64_32(uint64_t *n, uint32_t base) +/* Not needed on 64bit architectures */ +#if BITS_PER_LONG == 32 + +#ifndef __div64_32 +uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base) { uint64_t rem = *n; uint64_t b = base; @@ -52,3 +57,129 @@ uint32_t notrace __div64_32(uint64_t *n, uint32_t base) *n = res; return rem; } +EXPORT_SYMBOL(__div64_32); +#endif + +#ifndef div_s64_rem +s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) +{ + u64 quotient; + + if (dividend < 0) { + quotient = div_u64_rem(-dividend, abs(divisor), (u32 *)remainder); + *remainder = -*remainder; + if (divisor > 0) + quotient = -quotient; + } else { + quotient = div_u64_rem(dividend, abs(divisor), (u32 *)remainder); + if (divisor < 0) + quotient = -quotient; + } + return quotient; +} +EXPORT_SYMBOL(div_s64_rem); +#endif + +/** + * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder + * @dividend: 64bit dividend + * @divisor: 64bit divisor + * @remainder: 64bit remainder + * + * This implementation is a comparable to algorithm used by div64_u64. + * But this operation, which includes math for calculating the remainder, + * is kept distinct to avoid slowing down the div64_u64 operation on 32bit + * systems. + */ +#ifndef div64_u64_rem +u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) +{ + u32 high = divisor >> 32; + u64 quot; + + if (high == 0) { + u32 rem32; + quot = div_u64_rem(dividend, divisor, &rem32); + *remainder = rem32; + } else { + int n = 1 + fls(high); + quot = div_u64(dividend >> n, divisor >> n); + + if (quot != 0) + quot--; + + *remainder = dividend - quot * divisor; + if (*remainder >= divisor) { + quot++; + *remainder -= divisor; + } + } + + return quot; +} +EXPORT_SYMBOL(div64_u64_rem); +#endif + +/** + * div64_u64 - unsigned 64bit divide with 64bit divisor + * @dividend: 64bit dividend + * @divisor: 64bit divisor + * + * This implementation is a modified version of the algorithm proposed + * by the book 'Hacker's Delight'. The original source and full proof + * can be found here and is available for use without restriction. + * + * 'http://www.hackersdelight.org/hdcodetxt/divDouble.c.txt' + */ +#ifndef div64_u64 +u64 div64_u64(u64 dividend, u64 divisor) +{ + u32 high = divisor >> 32; + u64 quot; + + if (high == 0) { + quot = div_u64(dividend, divisor); + } else { + int n = 1 + fls(high); + quot = div_u64(dividend >> n, divisor >> n); + + if (quot != 0) + quot--; + if ((dividend - quot * divisor) >= divisor) + quot++; + } + + return quot; +} +EXPORT_SYMBOL(div64_u64); +#endif + +/** + * div64_s64 - signed 64bit divide with 64bit divisor + * @dividend: 64bit dividend + * @divisor: 64bit divisor + */ +#ifndef div64_s64 +s64 div64_s64(s64 dividend, s64 divisor) +{ + s64 quot, t; + + quot = div64_u64(abs(dividend), abs(divisor)); + t = (dividend ^ divisor) >> 63; + + return (quot ^ t) - t; +} +EXPORT_SYMBOL(div64_s64); +#endif + +#endif /* BITS_PER_LONG == 32 */ + +/* + * Iterative div/mod for use when dividend is not expected to be much + * bigger than divisor. + */ +u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) +{ + return __iter_div_u64_rem(dividend, divisor, remainder); +} +EXPORT_SYMBOL(iter_div_u64_rem); |