diff --git a/core/sys/darwin/bitop.c b/core/sys/darwin/bitop.c
new file mode 100644
index 0000000..141f252
--- /dev/null
+++ b/core/sys/darwin/bitop.c
@@ -0,0 +1,16 @@
+#include <blue/core/bitop.h>
+
+int b_popcountl(long v)
+{
+	return __builtin_popcountl(v);
+}
+
+int b_ctzl(long v)
+{
+	return __builtin_ctzl(v);
+}
+
+int b_clzl(long v)
+{
+	return __builtin_clzl(v);
+}
diff --git a/core/sys/linux/bitop.c b/core/sys/linux/bitop.c
new file mode 100644
index 0000000..141f252
--- /dev/null
+++ b/core/sys/linux/bitop.c
@@ -0,0 +1,16 @@
+#include <blue/core/bitop.h>
+
+int b_popcountl(long v)
+{
+	return __builtin_popcountl(v);
+}
+
+int b_ctzl(long v)
+{
+	return __builtin_ctzl(v);
+}
+
+int b_clzl(long v)
+{
+	return __builtin_clzl(v);
+}