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-rw-r--r--src/common/bit_util.h49
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
16namespace Common { 13namespace 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