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Added 8, 16 & 64 bit versions of count_trailing_zeros

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jwellbelove 2017-01-04 17:51:36 +00:00
parent 5c0ea58c81
commit 09fda198ec
1 changed files with 135 additions and 9 deletions
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144
src/binary.h
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@ -564,13 +564,12 @@ namespace etl
return signed_value;
}
#if ETL_8BIT_SUPPORT
//***************************************************************************
/// Count trailing zeros.
/// Count trailing zeros. bit.
/// Uses a binary search.
//***************************************************************************
template <typename T>
typename etl::enable_if<etl::is_same<typename etl::make_unsigned<T>::type, uint32_t>::value, uint_least8_t>::type
count_trailing_zeros(uint32_t value)
uint_least8_t count_trailing_zeros(uint8_t value)
{
uint_least8_t count;
@ -582,19 +581,146 @@ namespace etl
{
count = 1;
if ((value & 0xffff) == 0)
if ((value & 0xF) == 0)
{
value >>= 16;
count += 16;
value >>= 4;
count += 4;
}
if ((value & 0xff) == 0)
if ((value & 0x3) == 0)
{
value >>= 2;
count += 2;
}
count -= value & 0x1;
}
return count;
}
#endif
//***************************************************************************
/// Count trailing zeros. 16bit.
/// Uses a binary search.
//***************************************************************************
uint_least8_t count_trailing_zeros(uint16_t value)
{
uint_least8_t count;
if (value & 0x1)
{
count = 0;
}
else
{
count = 1;
if ((value & 0xFF) == 0)
{
value >>= 8;
count += 8;
}
if ((value & 0xf) == 0)
if ((value & 0xF) == 0)
{
value >>= 4;
count += 4;
}
if ((value & 0x3) == 0)
{
value >>= 2;
count += 2;
}
count -= value & 0x1;
}
return count;
}
//***************************************************************************
/// Count trailing zeros. 32bit.
/// Uses a binary search.
//***************************************************************************
uint_least8_t count_trailing_zeros(uint32_t value)
{
uint_least8_t count;
if (value & 0x1)
{
count = 0;
}
else
{
count = 1;
if ((value & 0xFFFF) == 0)
{
value >>= 16;
count += 16;
}
if ((value & 0xFF) == 0)
{
value >>= 8;
count += 8;
}
if ((value & 0xF) == 0)
{
value >>= 4;
count += 4;
}
if ((value & 0x3) == 0)
{
value >>= 2;
count += 2;
}
count -= value & 0x1;
}
return count;
}
//***************************************************************************
/// Count trailing zeros. 64bit.
/// Uses a binary search.
//***************************************************************************
uint_least8_t count_trailing_zeros(uint64_t value)
{
uint_least8_t count;
if (value & 0x1)
{
count = 0;
}
else
{
count = 1;
if ((value & 0xFFFFFFFF) == 0)
{
value >>= 32;
count += 32;
}
if ((value & 0xFFFF) == 0)
{
value >>= 16;
count += 16;
}
if ((value & 0xFF) == 0)
{
value >>= 8;
count += 8;
}
if ((value & 0xF) == 0)
{
value >>= 4;
count += 4;