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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/import/chips/p9/procedures/hwp/memory/lib/utils/bit_count.H $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2015,2017 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
///
/// @file bit_count.H
/// @brief count bits
///
// *HWP HWP Owner: Stephen Glancy <sglancy@us.ibm.com>
// *HWP HWP Backup: Andre Marin <aamarin@us.ibm.com>
// *HWP Team: Memory
// *HWP Level: 3
// *HWP Consumed by: HB:FSP
#ifndef _MSS_BIT_COUNT_H_
#define _MSS_BIT_COUNT_H_
#include <fapi2.H>
namespace mss
{
///
/// @brief Count the bits in a T which are set (1)
/// @tparam T an integral type. e.g., uint64_t, uint8_t
/// @param[in] i_value the value to check, count
/// @return uint64_t the number of bits set in the input
///
template< typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
inline uint64_t bit_count(const T& i_value)
{
if (i_value == 0)
{
return 0;
}
else
{
return bit_count(i_value >> 1) + (i_value & 0x01);
}
}
///
/// @brief Return the bit position of the first bit set, from the left
/// @tparam T, an integral type. e.g., uint64_t, uint8_t
/// @param[in] i_value the value to check
/// @return uint64_t the bit position of the first set bit
/// @bote assumes you checked to make sure there were bits set because it will return 0
///
template< typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
inline uint64_t first_bit_set(const T& i_value, const uint64_t i_pos = 0)
{
if (i_value == 0)
{
return 0;
}
if (fapi2::buffer<T>(i_value).template getBit(i_pos))
{
return i_pos;
}
else
{
return first_bit_set(i_value, i_pos + 1);
}
}
}
#endif
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