diff --git a/cpu/ppc/ppcemu.h b/cpu/ppc/ppcemu.h
index 481be6c..b9c8694 100644
--- a/cpu/ppc/ppcemu.h
+++ b/cpu/ppc/ppcemu.h
@@ -35,7 +35,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 //#define ILLEGAL_OP_SAFE 1
 
 // Uncomment this to use GCC built-in functions.
-//#define USE_GCC_BUILTINS 1
+#define USE_GCC_BUILTINS 1
 
 // Uncomment this to use Visual Studio built-in functions.
 //#define USE_VS_BUILTINS 1
diff --git a/cpu/ppc/ppcopcodes.cpp b/cpu/ppc/ppcopcodes.cpp
index 21c3e21..70e81d3 100644
--- a/cpu/ppc/ppcopcodes.cpp
+++ b/cpu/ppc/ppcopcodes.cpp
@@ -516,15 +516,16 @@ void dppc_interpreter::ppc_neg() {
 void dppc_interpreter::ppc_cntlzw() {
     ppc_grab_regssa();
 
-    uint32_t lead;
     uint32_t bit_check = ppc_result_d;
 
 #ifdef USE_GCC_BUILTINS
-    lead = !bit_check ? 32 : __builtin_clz(bit_check);
+    uint32_t lead = !bit_check ? 32 : __builtin_clz(bit_check);
 #elif defined USE_VS_BUILTINS
-    lead = __lzcnt(bit_check);
+    uint32_t lead = __lzcnt(bit_check);
 #else
-    for (uint32_t mask = 0x80000000UL, lead = 0; mask; lead++, mask >>= 1) {
+    uint32_t lead, mask;
+
+    for (mask = 0x80000000UL, lead = 0; mask != 0; lead++, mask >>= 1) {
         if (bit_check & mask)
             break;
     }