math_bits_inline.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#ifndef __MATH_BITS_INLINE_C__
#define __MATH_BITS_INLINE_C__
 
#ifdef _MSC_VER
#  include <intrin.h>
#endif
 
#include "BLI_assert.h"
#include "BLI_math_bits.h"
 
MINLINE unsigned int bitscan_forward_uint(unsigned int a)
{
  BLI_assert(a != 0);
#ifdef _MSC_VER
  unsigned long ctz;
  _BitScanForward(&ctz, a);
  return ctz;
#else
  return (unsigned int)__builtin_ctz(a);
#endif
}
 
MINLINE unsigned int bitscan_forward_uint64(unsigned long long a)
{
  BLI_assert(a != 0);
#ifdef _MSC_VER
  unsigned long ctz;
  _BitScanForward64(&ctz, a);
  return ctz;
#else
  return (unsigned int)__builtin_ctzll(a);
#endif
}
 
MINLINE int bitscan_forward_i(int a)
{
  return (int)bitscan_forward_uint((unsigned int)a);
}
 
MINLINE unsigned int bitscan_forward_clear_uint(unsigned int *a)
{
  unsigned int i = bitscan_forward_uint(*a);
  *a &= (*a) - 1;
  return i;
}
 
MINLINE int bitscan_forward_clear_i(int *a)
{
  return (int)bitscan_forward_clear_uint((unsigned int *)a);
}
 
MINLINE unsigned int bitscan_reverse_uint(unsigned int a)
{
  BLI_assert(a != 0);
#ifdef _MSC_VER
  unsigned long clz;
  _BitScanReverse(&clz, a);
  return 31 - clz;
#else
  return (unsigned int)__builtin_clz(a);
#endif
}
 
MINLINE unsigned int bitscan_reverse_uint64(unsigned long long a)
{
  BLI_assert(a != 0);
#ifdef _MSC_VER
  unsigned long clz;
  _BitScanReverse64(&clz, a);
  return 63 - clz;
#else
  return (unsigned int)__builtin_clzll(a);
#endif
}
 
MINLINE int bitscan_reverse_i(int a)
{
  return (int)bitscan_reverse_uint((unsigned int)a);
}
 
MINLINE unsigned int bitscan_reverse_clear_uint(unsigned int *a)
{
  unsigned int i = bitscan_reverse_uint(*a);
  *a &= ~(0x80000000 >> i);
  return i;
}
 
MINLINE int bitscan_reverse_clear_i(int *a)
{
  return (int)bitscan_reverse_clear_uint((unsigned int *)a);
}
 
MINLINE unsigned int highest_order_bit_uint(unsigned int n)
{
  if (n == 0) {
    return 0;
  }
  return 1 << (sizeof(unsigned int) * 8 - bitscan_reverse_uint(n));
}
 
MINLINE unsigned short highest_order_bit_s(unsigned short n)
{
  n |= (unsigned short)(n >> 1);
  n |= (unsigned short)(n >> 2);
  n |= (unsigned short)(n >> 4);
  n |= (unsigned short)(n >> 8);
  return (unsigned short)(n - (n >> 1));
}
 
#if !(COMPILER_GCC || COMPILER_CLANG || COMPILER_MSVC)
MINLINE int count_bits_i(unsigned int i)
{
  /* variable-precision SWAR algorithm. */
  i = i - ((i >> 1) & 0x55555555);
  i = (i & 0x33333333) + ((i >> 2) & 0x33333333);
  return (((i + (i >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24;
}
MINLINE int count_bits_uint64(const uint64_t a)
{
  return count_bits_i((uint32_t)a) + count_bits_i((uint32_t)(a >> 32));
}
#endif
 
MINLINE int float_as_int(float f)
{
  union {
    int i;
    float f;
  } u;
  u.f = f;
  return u.i;
}
 
MINLINE unsigned int float_as_uint(float f)
{
  union {
    unsigned int i;
    float f;
  } u;
  u.f = f;
  return u.i;
}
 
MINLINE float int_as_float(int i)
{
  union {
    int i;
    float f;
  } u;
  u.i = i;
  return u.f;
}
 
MINLINE float uint_as_float(unsigned int i)
{
  union {
    unsigned int i;
    float f;
  } u;
  u.i = i;
  return u.f;
}
 
MINLINE float xor_fl(float x, int y)
{
  return int_as_float(float_as_int(x) ^ y);
}
 
#endif /* __MATH_BITS_INLINE_C__ */