math.h File Reference

#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <derive-c/core/attributes.h>
#include <derive-c/core/panic.h>

Go to the source code of this file.

Macros
#define	DC_MATH_IS_POWER_OF_2(x)
#define	DC_MATH_MSB_INDEX(x)

Functions
static DC_INLINE DC_CONST size_t	dc_math_next_power_of_2 (size_t x)
static size_t DC_INLINE DC_CONST	dc_math_modulus_power_of_2_capacity (size_t index, size_t capacity)
static bool DC_INLINE DC_CONST	dc_math_is_aligned_pow2_exp (const void *ptr, unsigned exp)

Macro Definition Documentation

DC_MATH_IS_POWER_OF_2

#define DC_MATH_IS_POWER_OF_2

(

x

)

Value:

((x) != 0 && ((x) & ((x) - 1)) == 0)

Definition at line 12 of file math.h.

DC_MATH_MSB_INDEX

#define DC_MATH_MSB_INDEX

(

x

)

Value:

        ((x) == 0 ? 0                                                                              \
                  : _Generic((x),                                                                  \
                 uint8_t: (7u - __builtin_clz((uint32_t)((x)) << 24)),                             \
                 uint16_t: (15u - __builtin_clz((uint32_t)((x)) << 16)),                           \
                 uint32_t: (31u - __builtin_clz((uint32_t)(x))),                                   \
                 uint64_t: (63u - __builtin_clzll((uint64_t)(x)))))

Definition at line 38 of file math.h.

    #define DC_MATH_MSB_INDEX(x)                                                                   \
        ((x) == 0 ? 0                                                                              \
                  : _Generic((x),                                                                  \
                 uint8_t: (7u - __builtin_clz((uint32_t)((x)) << 24)),                             \
                 uint16_t: (15u - __builtin_clz((uint32_t)((x)) << 16)),                           \
                 uint32_t: (31u - __builtin_clz((uint32_t)(x))),                                   \
                 uint64_t: (63u - __builtin_clzll((uint64_t)(x)))))

Function Documentation

dc_math_is_aligned_pow2_exp()

bool DC_INLINE DC_CONST dc_math_is_aligned_pow2_exp ( const void * ptr, unsigned exp )

static

Definition at line 69 of file math.h.

                                                                                          {
    uintptr_t const mask = (1U << exp) - 1;
    return (((uintptr_t)ptr) & mask) == 0;
}

dc_math_modulus_power_of_2_capacity()

size_t DC_INLINE DC_CONST dc_math_modulus_power_of_2_capacity ( size_t index, size_t capacity )

static

Definition at line 63 of file math.h.

                                                                                      {
    DC_ASSUME(DC_MATH_IS_POWER_OF_2(capacity));
    return index & (capacity - 1);
}

dc_math_next_power_of_2()

DC_INLINE DC_CONST size_t dc_math_next_power_of_2 ( size_t x )

static

Definition at line 48 of file math.h.

                                                                   {
    if (x == 0)
        return 1;
    x--;
    x |= x >> 1;
    x |= x >> 2;
    x |= x >> 4;
    x |= x >> 8;
    x |= x >> 16;
#if SIZE_MAX > 0xFFFFFFFF
    x |= x >> 32; // For 64-bit platforms
#endif
    return x + 1;
}