Current File : //usr/src/linux-headers-5.15.0-125-generic/include/linux/math.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MATH_H
#define _LINUX_MATH_H
#include <asm/div64.h>
#include <uapi/linux/kernel.h>
/*
* This looks more complex than it should be. But we need to
* get the type for the ~ right in round_down (it needs to be
* as wide as the result!), and we want to evaluate the macro
* arguments just once each.
*/
#define __round_mask(x, y) ((__typeof__(x))((y)-1))
/**
* round_up - round up to next specified power of 2
* @x: the value to round
* @y: multiple to round up to (must be a power of 2)
*
* Rounds @x up to next multiple of @y (which must be a power of 2).
* To perform arbitrary rounding up, use roundup() below.
*/
#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
/**
* round_down - round down to next specified power of 2
* @x: the value to round
* @y: multiple to round down to (must be a power of 2)
*
* Rounds @x down to next multiple of @y (which must be a power of 2).
* To perform arbitrary rounding down, use rounddown() below.
*/
#define round_down(x, y) ((x) & ~__round_mask(x, y))
#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
#define DIV_ROUND_DOWN_ULL(ll, d) \
({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
#define DIV_ROUND_UP_ULL(ll, d) \
DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d))
#if BITS_PER_LONG == 32
# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
#else
# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
#endif
/**
* roundup - round up to the next specified multiple
* @x: the value to up
* @y: multiple to round up to
*
* Rounds @x up to next multiple of @y. If @y will always be a power
* of 2, consider using the faster round_up().
*/
#define roundup(x, y) ( \
{ \
typeof(y) __y = y; \
(((x) + (__y - 1)) / __y) * __y; \
} \
)
/**
* rounddown - round down to next specified multiple
* @x: the value to round
* @y: multiple to round down to
*
* Rounds @x down to next multiple of @y. If @y will always be a power
* of 2, consider using the faster round_down().
*/
#define rounddown(x, y) ( \
{ \
typeof(x) __x = (x); \
__x - (__x % (y)); \
} \
)
/*
* Divide positive or negative dividend by positive or negative divisor
* and round to closest integer. Result is undefined for negative
* divisors if the dividend variable type is unsigned and for negative
* dividends if the divisor variable type is unsigned.
*/
#define DIV_ROUND_CLOSEST(x, divisor)( \
{ \
typeof(x) __x = x; \
typeof(divisor) __d = divisor; \
(((typeof(x))-1) > 0 || \
((typeof(divisor))-1) > 0 || \
(((__x) > 0) == ((__d) > 0))) ? \
(((__x) + ((__d) / 2)) / (__d)) : \
(((__x) - ((__d) / 2)) / (__d)); \
} \
)
/*
* Same as above but for u64 dividends. divisor must be a 32-bit
* number.
*/
#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
{ \
typeof(divisor) __d = divisor; \
unsigned long long _tmp = (x) + (__d) / 2; \
do_div(_tmp, __d); \
_tmp; \
} \
)
/*
* Multiplies an integer by a fraction, while avoiding unnecessary
* overflow or loss of precision.
*/
#define mult_frac(x, numer, denom)( \
{ \
typeof(x) quot = (x) / (denom); \
typeof(x) rem = (x) % (denom); \
(quot * (numer)) + ((rem * (numer)) / (denom)); \
} \
)
#define sector_div(a, b) do_div(a, b)
/**
* abs - return absolute value of an argument
* @x: the value. If it is unsigned type, it is converted to signed type first.
* char is treated as if it was signed (regardless of whether it really is)
* but the macro's return type is preserved as char.
*
* Return: an absolute value of x.
*/
#define abs(x) __abs_choose_expr(x, long long, \
__abs_choose_expr(x, long, \
__abs_choose_expr(x, int, \
__abs_choose_expr(x, short, \
__abs_choose_expr(x, char, \
__builtin_choose_expr( \
__builtin_types_compatible_p(typeof(x), char), \
(char)({ signed char __x = (x); __x<0?-__x:__x; }), \
((void)0)))))))
#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
__builtin_types_compatible_p(typeof(x), signed type) || \
__builtin_types_compatible_p(typeof(x), unsigned type), \
({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
/**
* reciprocal_scale - "scale" a value into range [0, ep_ro)
* @val: value
* @ep_ro: right open interval endpoint
*
* Perform a "reciprocal multiplication" in order to "scale" a value into
* range [0, @ep_ro), where the upper interval endpoint is right-open.
* This is useful, e.g. for accessing a index of an array containing
* @ep_ro elements, for example. Think of it as sort of modulus, only that
* the result isn't that of modulo. ;) Note that if initial input is a
* small value, then result will return 0.
*
* Return: a result based on @val in interval [0, @ep_ro).
*/
static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
{
return (u32)(((u64) val * ep_ro) >> 32);
}
u64 int_pow(u64 base, unsigned int exp);
unsigned long int_sqrt(unsigned long);
#if BITS_PER_LONG < 64
u32 int_sqrt64(u64 x);
#else
static inline u32 int_sqrt64(u64 x)
{
return (u32)int_sqrt(x);
}
#endif
#endif /* _LINUX_MATH_H */
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