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-rw-r--r--src/common/bit_util.h45
1 files changed, 33 insertions, 12 deletions
diff --git a/src/common/bit_util.h b/src/common/bit_util.h
index 14e53c273..70e728a5e 100644
--- a/src/common/bit_util.h
+++ b/src/common/bit_util.h
@@ -59,22 +59,43 @@ inline u64 CountLeadingZeroes64(u64 value) {
}
#endif
+
+#ifdef _MSC_VER
inline u32 CountTrailingZeroes32(u32 value) {
- u32 count = 0;
- while (((value >> count) & 0xf) == 0 && count < 32)
- count += 4;
- while (((value >> count) & 1) == 0 && count < 32)
- count++;
- return count;
+ unsigned long trailing_zero = 0;
+
+ if (_BitScanForward(&trailing_zero, value) != 0) {
+ return trailing_zero;
+ }
+
+ return 32;
}
inline u64 CountTrailingZeroes64(u64 value) {
- u64 count = 0;
- while (((value >> count) & 0xf) == 0 && count < 64)
- count += 4;
- while (((value >> count) & 1) == 0 && count < 64)
- count++;
- return count;
+ unsigned long trailing_zero = 0;
+
+ if (_BitScanForward64(&trailing_zero, value) != 0) {
+ return trailing_zero;
+ }
+
+ return 64;
}
+#else
+inline u32 CountTrailingZeroes32(u32 value) {
+ if (value == 0) {
+ return 32;
+ }
+
+ return __builtin_ctz(value);
+}
+
+inline u64 CountTrailingZeroes64(u64 value) {
+ if (value == 0) {
+ return 64;
+ }
+
+ return __builtin_ctzll(value);
+}
+#endif
} // namespace Common