linux-stable/include/linux/math64.h
Linus Torvalds 7832681b36 A relatively calm cycle for the docs tree again.
- The old driver statement has been added to the kernel docs.
 
   - We have a couple of new helper scripts.  find-unused-docs.sh from Sayli
     Karnic will point out kerneldoc comments that are not actually used in
     the documentation.  Jani Nikula's documentation-file-ref-check finds
     references to non-existing files.
 
   - A new ftrace document from Steve Rostedt.
 
   - Vinod Koul converted the dmaengine docs to RST
 
 Beyond that, it's mostly simple fixes.
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Merge tag 'docs-4.15' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A relatively calm cycle for the docs tree again.

  - The old driver statement has been added to the kernel docs.

  - We have a couple of new helper scripts. find-unused-docs.sh from
    Sayli Karnic will point out kerneldoc comments that are not actually
    used in the documentation. Jani Nikula's
    documentation-file-ref-check finds references to non-existing files.

  - A new ftrace document from Steve Rostedt.

  - Vinod Koul converted the dmaengine docs to RST

  Beyond that, it's mostly simple fixes.

  This set reaches outside of Documentation/ a bit more than most. In
  all cases, the changes are to comment docs, mostly from Randy, in
  places where there didn't seem to be anybody better to take them"

* tag 'docs-4.15' of git://git.lwn.net/linux: (52 commits)
  documentation: fb: update list of available compiled-in fonts
  MAINTAINERS: update DMAengine documentation location
  dmaengine: doc: ReSTize pxa_dma doc
  dmaengine: doc: ReSTize dmatest doc
  dmaengine: doc: ReSTize client API doc
  dmaengine: doc: ReSTize provider doc
  dmaengine: doc: Add ReST style dmaengine document
  ftrace/docs: Add documentation on how to use ftrace from within the kernel
  bug-hunting.rst: Fix an example and a typo in a Sphinx tag
  scripts: Add a script to find unused documentation
  samples: Convert timers to use timer_setup()
  documentation: kernel-api: add more info on bitmap functions
  Documentation: fix selftests related file refs
  Documentation: fix ref to power basic-pm-debugging
  Documentation: fix ref to trace stm content
  Documentation: fix ref to coccinelle content
  Documentation: fix ref to workqueue content
  Documentation: fix ref to sphinx/kerneldoc.py
  Documentation: fix locking rt-mutex doc refs
  docs: dev-tools: correct Coccinelle version number
  ...
2017-11-13 08:25:06 -08:00

284 lines
6.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MATH64_H
#define _LINUX_MATH64_H
#include <linux/types.h>
#include <asm/div64.h>
#if BITS_PER_LONG == 64
#define div64_long(x, y) div64_s64((x), (y))
#define div64_ul(x, y) div64_u64((x), (y))
/**
* div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
* @dividend: unsigned 64bit dividend
* @divisor: unsigned 32bit divisor
* @remainder: pointer to unsigned 32bit remainder
*
* Return: sets ``*remainder``, then returns dividend / divisor
*
* This is commonly provided by 32bit archs to provide an optimized 64bit
* divide.
*/
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
*remainder = dividend % divisor;
return dividend / divisor;
}
/**
* div_s64_rem - signed 64bit divide with 32bit divisor with remainder
* @dividend: signed 64bit dividend
* @divisor: signed 32bit divisor
* @remainder: pointer to signed 32bit remainder
*
* Return: sets ``*remainder``, then returns dividend / divisor
*/
static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
{
*remainder = dividend % divisor;
return dividend / divisor;
}
/**
* div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
* @dividend: unsigned 64bit dividend
* @divisor: unsigned 64bit divisor
* @remainder: pointer to unsigned 64bit remainder
*
* Return: sets ``*remainder``, then returns dividend / divisor
*/
static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
{
*remainder = dividend % divisor;
return dividend / divisor;
}
/**
* div64_u64 - unsigned 64bit divide with 64bit divisor
* @dividend: unsigned 64bit dividend
* @divisor: unsigned 64bit divisor
*
* Return: dividend / divisor
*/
static inline u64 div64_u64(u64 dividend, u64 divisor)
{
return dividend / divisor;
}
/**
* div64_s64 - signed 64bit divide with 64bit divisor
* @dividend: signed 64bit dividend
* @divisor: signed 64bit divisor
*
* Return: dividend / divisor
*/
static inline s64 div64_s64(s64 dividend, s64 divisor)
{
return dividend / divisor;
}
#elif BITS_PER_LONG == 32
#define div64_long(x, y) div_s64((x), (y))
#define div64_ul(x, y) div_u64((x), (y))
#ifndef div_u64_rem
static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
{
*remainder = do_div(dividend, divisor);
return dividend;
}
#endif
#ifndef div_s64_rem
extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
#endif
#ifndef div64_u64_rem
extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
#endif
#ifndef div64_u64
extern u64 div64_u64(u64 dividend, u64 divisor);
#endif
#ifndef div64_s64
extern s64 div64_s64(s64 dividend, s64 divisor);
#endif
#endif /* BITS_PER_LONG */
/**
* div_u64 - unsigned 64bit divide with 32bit divisor
* @dividend: unsigned 64bit dividend
* @divisor: unsigned 32bit divisor
*
* This is the most common 64bit divide and should be used if possible,
* as many 32bit archs can optimize this variant better than a full 64bit
* divide.
*/
#ifndef div_u64
static inline u64 div_u64(u64 dividend, u32 divisor)
{
u32 remainder;
return div_u64_rem(dividend, divisor, &remainder);
}
#endif
/**
* div_s64 - signed 64bit divide with 32bit divisor
* @dividend: signed 64bit dividend
* @divisor: signed 32bit divisor
*/
#ifndef div_s64
static inline s64 div_s64(s64 dividend, s32 divisor)
{
s32 remainder;
return div_s64_rem(dividend, divisor, &remainder);
}
#endif
u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
static __always_inline u32
__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
{
u32 ret = 0;
while (dividend >= divisor) {
/* The following asm() prevents the compiler from
optimising this loop into a modulo operation. */
asm("" : "+rm"(dividend));
dividend -= divisor;
ret++;
}
*remainder = dividend;
return ret;
}
#ifndef mul_u32_u32
/*
* Many a GCC version messes this up and generates a 64x64 mult :-(
*/
static inline u64 mul_u32_u32(u32 a, u32 b)
{
return (u64)a * b;
}
#endif
#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
#ifndef mul_u64_u32_shr
static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
{
return (u64)(((unsigned __int128)a * mul) >> shift);
}
#endif /* mul_u64_u32_shr */
#ifndef mul_u64_u64_shr
static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
{
return (u64)(((unsigned __int128)a * mul) >> shift);
}
#endif /* mul_u64_u64_shr */
#else
#ifndef mul_u64_u32_shr
static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
{
u32 ah, al;
u64 ret;
al = a;
ah = a >> 32;
ret = mul_u32_u32(al, mul) >> shift;
if (ah)
ret += mul_u32_u32(ah, mul) << (32 - shift);
return ret;
}
#endif /* mul_u64_u32_shr */
#ifndef mul_u64_u64_shr
static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
{
union {
u64 ll;
struct {
#ifdef __BIG_ENDIAN
u32 high, low;
#else
u32 low, high;
#endif
} l;
} rl, rm, rn, rh, a0, b0;
u64 c;
a0.ll = a;
b0.ll = b;
rl.ll = mul_u32_u32(a0.l.low, b0.l.low);
rm.ll = mul_u32_u32(a0.l.low, b0.l.high);
rn.ll = mul_u32_u32(a0.l.high, b0.l.low);
rh.ll = mul_u32_u32(a0.l.high, b0.l.high);
/*
* Each of these lines computes a 64-bit intermediate result into "c",
* starting at bits 32-95. The low 32-bits go into the result of the
* multiplication, the high 32-bits are carried into the next step.
*/
rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
rh.l.high = (c >> 32) + rh.l.high;
/*
* The 128-bit result of the multiplication is in rl.ll and rh.ll,
* shift it right and throw away the high part of the result.
*/
if (shift == 0)
return rl.ll;
if (shift < 64)
return (rl.ll >> shift) | (rh.ll << (64 - shift));
return rh.ll >> (shift & 63);
}
#endif /* mul_u64_u64_shr */
#endif
#ifndef mul_u64_u32_div
static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
{
union {
u64 ll;
struct {
#ifdef __BIG_ENDIAN
u32 high, low;
#else
u32 low, high;
#endif
} l;
} u, rl, rh;
u.ll = a;
rl.ll = mul_u32_u32(u.l.low, mul);
rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high;
/* Bits 32-63 of the result will be in rh.l.low. */
rl.l.high = do_div(rh.ll, divisor);
/* Bits 0-31 of the result will be in rl.l.low. */
do_div(rl.ll, divisor);
rl.l.high = rh.l.low;
return rl.ll;
}
#endif /* mul_u64_u32_div */
#endif /* _LINUX_MATH64_H */