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-rw-r--r--src/common/bit_util.h44
1 files changed, 44 insertions, 0 deletions
diff --git a/src/common/bit_util.h b/src/common/bit_util.h
index d032df413..6f7d5a947 100644
--- a/src/common/bit_util.h
+++ b/src/common/bit_util.h
@@ -97,4 +97,48 @@ inline u32 CountTrailingZeroes64(u64 value) {
}
#endif
+#ifdef _MSC_VER
+
+inline u32 MostSignificantBit32(const u32 value) {
+ unsigned long result;
+ _BitScanReverse(&result, value);
+ return static_cast<u32>(result);
+}
+
+inline u32 MostSignificantBit64(const u64 value) {
+ unsigned long result;
+ _BitScanReverse64(&result, value);
+ return static_cast<u32>(result);
+}
+
+#else
+
+inline u32 MostSignificantBit32(const u32 value) {
+ return 31U - static_cast<u32>(__builtin_clz(value));
+}
+
+inline u32 MostSignificantBit64(const u64 value) {
+ return 63U - static_cast<u32>(__builtin_clzll(value));
+}
+
+#endif
+
+inline u32 Log2Floor32(const u32 value) {
+ return MostSignificantBit32(value);
+}
+
+inline u32 Log2Ceil32(const u32 value) {
+ const u32 log2_f = Log2Floor32(value);
+ return log2_f + ((value ^ (1U << log2_f)) != 0U);
+}
+
+inline u32 Log2Floor64(const u64 value) {
+ return MostSignificantBit64(value);
+}
+
+inline u32 Log2Ceil64(const u64 value) {
+ const u64 log2_f = static_cast<u64>(Log2Floor64(value));
+ return static_cast<u32>(log2_f + ((value ^ (1ULL << log2_f)) != 0ULL));
+}
+
} // namespace Common