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Replace FindFirstBit/FindFirstBit64 with a single template function

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This commit is contained in:
Jonathan G Rennison
2021-11-01 23:00:44 +00:00
parent d585ce75dd
commit 1e0bea5b8d
8 changed files with 41 additions and 37 deletions
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51
src/core/bitmath_func.hpp
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@@ -187,21 +187,7 @@ static inline T ToggleBit(T &x, const uint8 y)
#ifdef WITH_BITMATH_BUILTINS
#define FIND_FIRST_BIT(x) FindFirstBit(x)
inline uint8 FindFirstBit(uint32 x)
{
if (x == 0) return 0;
return __builtin_ctz(x);
}
inline uint8 FindFirstBit64(uint64 x)
{
if (x == 0) return 0;
return __builtin_ctzll(x);
}
#define FIND_FIRST_BIT(x) FindFirstBit<uint>(x)
#else
@@ -220,11 +206,39 @@ extern const uint8 _ffb_64[64];
*/
#define FIND_FIRST_BIT(x) _ffb_64[(x)]
uint8 FindFirstBit(uint32 x);
uint8 FindFirstBit64(uint64 x);
#endif
/**
* Search the first set bit in an integer variable.
*
* @param value The value to search
* @return The position of the first bit set, or 0 when value is 0
*/
template <typename T>
static inline uint8 FindFirstBit(T value)
{
static_assert(sizeof(T) <= sizeof(unsigned long long));
#ifdef WITH_BITMATH_BUILTINS
if (value == 0) return 0;
typename std::make_unsigned<T>::type unsigned_value = value;
if (sizeof(T) <= sizeof(unsigned int)) {
return __builtin_ctz(unsigned_value);
} else if (sizeof(T) == sizeof(unsigned long)) {
return __builtin_ctzl(unsigned_value);
} else {
return __builtin_ctzll(unsigned_value);
}
#else
if (sizeof(T) <= sizeof(uint32)) {
extern uint8 FindFirstBit32(x);
return FindFirstBit32(value);
} else {
extern uint8 FindFirstBit64(x);
return FindFirstBit64(value);
}
#endif
}
uint8 FindLastBit(uint64 x);
/**
@@ -275,6 +289,7 @@ static inline T KillFirstBit(T value)
template <typename T>
static inline uint CountBits(T value)
{
static_assert(sizeof(T) <= sizeof(unsigned long long));
#ifdef WITH_BITMATH_BUILTINS
typename std::make_unsigned<T>::type unsigned_value = value;
if (sizeof(T) <= sizeof(unsigned int)) {