overlrd2: ctz

game/overlord/jak3/pagemanager.cpp

@@ -0,0 +1,20 @@
+#include "pagemanager.h"
+
+namespace jak3 {
+
+static inline int ctz(u32 x) {
+  // Isolate lowest bit and subtract 1
+  x = (x & -x) - 1;
+
+  // popcount
+  x -= (x >> 1) & 0x55555555;
+  x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
+  x = (x + (x >> 4)) & 0x0f0f0f0f;
+  x += (x >> 8);
+  x += (x >> 16);
+  x &= 0x3f;
+
+  return static_cast<int>(x);
+}
+
+}  // namespace jak3