/* * 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))
/** * DIV_ROUND_UP_POW2 - divide and round up * @n: numerator * @d: denominator (must be a power of 2) * * Divides @n by @d and rounds up to next multiple of @d (which must be a power * of 2). Avoids integer overflows that may occur with __KERNEL_DIV_ROUND_UP(). * Performance is roughly equivalent to __KERNEL_DIV_ROUND_UP().
*/ #define DIV_ROUND_UP_POW2(n, d) \
((n) / (d) + !!((n) & ((d) - 1)))
/** * 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; \ unsignedlonglong _tmp = (x) + (__d) / 2; \
do_div(_tmp, __d); \
_tmp; \
} \
)
/* Calculate "x * n / d" without unnecessary overflow or loss of precision. */ #define mult_frac(x, n, d) \
({ \
typeof(x) x_ = (x); \
typeof(n) n_ = (n); \
typeof(d) d_ = (d); \
\
typeof(x_) q = x_ / d_; \
typeof(x_) r = x_ % d_; \
q * n_ + r * n_ / d_; \
})
#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, longlong, \
__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)({ signedchar __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)
/** * abs_diff - return absolute value of the difference between the arguments * @a: the first argument * @b: the second argument * * @a and @b have to be of the same type. With this restriction we compare * signed to signed and unsigned to unsigned. The result is the subtraction * the smaller of the two from the bigger, hence result is always a positive * value. * * Return: an absolute value of the difference between the @a and @b.
*/ #define abs_diff(a, b) ({ \
typeof(a) __a = (a); \
typeof(b) __b = (b); \
(void)(&__a == &__b); \
__a > __b ? (__a - __b) : (__b - __a); \
})
/** * 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).
*/ staticinline u32 reciprocal_scale(u32 val, u32 ep_ro)
{ return (u32)(((u64) val * ep_ro) >> 32);
}
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