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| -rw-r--r-- | src/import/generic/memory/lib/utils/bit_count.H | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/src/import/generic/memory/lib/utils/bit_count.H b/src/import/generic/memory/lib/utils/bit_count.H new file mode 100644 index 000000000..a489f6ea5 --- /dev/null +++ b/src/import/generic/memory/lib/utils/bit_count.H @@ -0,0 +1,89 @@ +/* IBM_PROLOG_BEGIN_TAG */ +/* This is an automatically generated prolog. */ +/* */ +/* $Source: src/import/generic/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: Brian Silver <bsilver@us.ibm.com> +// *HWP HWP Backup: Andre Marin <aamarin@us.ibm.com> +// *HWP Team: Memory +// *HWP Level: 2 +// *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<0>()) + { + return i_pos; + } + else + { + return first_bit_set(i_value << 1, i_pos + 1); + } +} + +} +#endif |
