diff options
Diffstat (limited to 'src/common/bit_util.h')
| -rw-r--r-- | src/common/bit_util.h | 49 |
1 files changed, 14 insertions, 35 deletions
diff --git a/src/common/bit_util.h b/src/common/bit_util.h index 685e7fc9b..64520ca4e 100644 --- a/src/common/bit_util.h +++ b/src/common/bit_util.h | |||
| @@ -4,13 +4,10 @@ | |||
| 4 | 4 | ||
| 5 | #pragma once | 5 | #pragma once |
| 6 | 6 | ||
| 7 | #include <bit> | ||
| 7 | #include <climits> | 8 | #include <climits> |
| 8 | #include <cstddef> | 9 | #include <cstddef> |
| 9 | 10 | ||
| 10 | #ifdef _MSC_VER | ||
| 11 | #include <intrin.h> | ||
| 12 | #endif | ||
| 13 | |||
| 14 | #include "common/common_types.h" | 11 | #include "common/common_types.h" |
| 15 | 12 | ||
| 16 | namespace Common { | 13 | namespace Common { |
| @@ -21,48 +18,30 @@ template <typename T> | |||
| 21 | return sizeof(T) * CHAR_BIT; | 18 | return sizeof(T) * CHAR_BIT; |
| 22 | } | 19 | } |
| 23 | 20 | ||
| 24 | #ifdef _MSC_VER | 21 | [[nodiscard]] constexpr u32 MostSignificantBit32(const u32 value) { |
| 25 | 22 | return 31U - static_cast<u32>(std::countl_zero(value)); | |
| 26 | [[nodiscard]] inline u32 MostSignificantBit32(const u32 value) { | ||
| 27 | unsigned long result; | ||
| 28 | _BitScanReverse(&result, value); | ||
| 29 | return static_cast<u32>(result); | ||
| 30 | } | ||
| 31 | |||
| 32 | [[nodiscard]] inline u32 MostSignificantBit64(const u64 value) { | ||
| 33 | unsigned long result; | ||
| 34 | _BitScanReverse64(&result, value); | ||
| 35 | return static_cast<u32>(result); | ||
| 36 | } | ||
| 37 | |||
| 38 | #else | ||
| 39 | |||
| 40 | [[nodiscard]] inline u32 MostSignificantBit32(const u32 value) { | ||
| 41 | return 31U - static_cast<u32>(__builtin_clz(value)); | ||
| 42 | } | 23 | } |
| 43 | 24 | ||
| 44 | [[nodiscard]] inline u32 MostSignificantBit64(const u64 value) { | 25 | [[nodiscard]] constexpr u32 MostSignificantBit64(const u64 value) { |
| 45 | return 63U - static_cast<u32>(__builtin_clzll(value)); | 26 | return 63U - static_cast<u32>(std::countl_zero(value)); |
| 46 | } | 27 | } |
| 47 | 28 | ||
| 48 | #endif | 29 | [[nodiscard]] constexpr u32 Log2Floor32(const u32 value) { |
| 49 | |||
| 50 | [[nodiscard]] inline u32 Log2Floor32(const u32 value) { | ||
| 51 | return MostSignificantBit32(value); | 30 | return MostSignificantBit32(value); |
| 52 | } | 31 | } |
| 53 | 32 | ||
| 54 | [[nodiscard]] inline u32 Log2Ceil32(const u32 value) { | 33 | [[nodiscard]] constexpr u32 Log2Floor64(const u64 value) { |
| 55 | const u32 log2_f = Log2Floor32(value); | 34 | return MostSignificantBit64(value); |
| 56 | return log2_f + ((value ^ (1U << log2_f)) != 0U); | ||
| 57 | } | 35 | } |
| 58 | 36 | ||
| 59 | [[nodiscard]] inline u32 Log2Floor64(const u64 value) { | 37 | [[nodiscard]] constexpr u32 Log2Ceil32(const u32 value) { |
| 60 | return MostSignificantBit64(value); | 38 | const u32 log2_f = Log2Floor32(value); |
| 39 | return log2_f + static_cast<u32>((value ^ (1U << log2_f)) != 0U); | ||
| 61 | } | 40 | } |
| 62 | 41 | ||
| 63 | [[nodiscard]] inline u32 Log2Ceil64(const u64 value) { | 42 | [[nodiscard]] constexpr u32 Log2Ceil64(const u64 value) { |
| 64 | const u64 log2_f = static_cast<u64>(Log2Floor64(value)); | 43 | const u64 log2_f = Log2Floor64(value); |
| 65 | return static_cast<u32>(log2_f + ((value ^ (1ULL << log2_f)) != 0ULL)); | 44 | return static_cast<u32>(log2_f + static_cast<u64>((value ^ (1ULL << log2_f)) != 0ULL)); |
| 66 | } | 45 | } |
| 67 | 46 | ||
| 68 | } // namespace Common | 47 | } // namespace Common |