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Added find first set/clear bit functions.

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This commit is contained in:
jwellbelove 2017-01-04 15:51:11 +00:00
parent c24d007d5c
commit 4bde024c03
1 changed files with 37 additions and 4 deletions
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41
src/binary.h
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@ -570,20 +570,39 @@ namespace etl
return signed_value;
}
//***************************************************************************
/// Find the value of the first set bit.
/// Starts from LSB.
//***************************************************************************
uint32_t first_set_bit(uint32_t value)
{
return (uint32_t)(value & -value);
}
//***************************************************************************
/// Find the position of the first set bit.
/// Starts from LSB.
//***************************************************************************
uint_least8_t find_first_set_bit(uint32_t value)
uint_least8_t first_set_bit_position(uint32_t value)
{
return __private_binary__::bit_position_lookup[((uint32_t)((value & -value) * 0x077CB531U)) >> 27];
return __private_binary__::bit_position_lookup[(first_set_bit(value) * 0x077CB531U) >> 27];
}
//***************************************************************************
/// Find the value of the first clear bit.
/// Starts from LSB.
//***************************************************************************
uint32_t first_clear_bit(uint32_t value)
{
value = ~value;
return (uint32_t)(value & -value);
}
//***************************************************************************
/// Find the position of the first clear bit.
/// Starts from LSB.
//***************************************************************************
uint_least8_t find_first_clear_bit(uint32_t value)
uint_least8_t first_clear_bit_position(uint32_t value)
{
value ~= value;
return __private_binary__::bit_position_lookup[((uint32_t)((value & -value) * 0x077CB531U)) >> 27];
@ -593,7 +612,21 @@ namespace etl
/// Find the position of the first bit that is clear or set.
/// Starts from LSB.
//***************************************************************************
uint_least8_t find_first_bit(bool state, uint32_t value)
uint_least8_t first_bit(bool state, uint32_t value)
{
if (!state)
{
value ~= value;
}
return (uint32_t)(value & -value);
}
//***************************************************************************
/// Find the position of the first bit that is clear or set.
/// Starts from LSB.
//***************************************************************************
uint_least8_t first_bit_position(bool state, uint32_t value)
{
if (!state)
{