diff --git a/include/strings.h b/include/strings.h
index 4d7d69c31ab06564e2fcfa19a7d3cc2f204ede0f..db0960b4eb87a5d5883d7c94ad6d9e5dca9d9633 100644
--- a/include/strings.h
+++ b/include/strings.h
@@ -22,6 +22,8 @@ char *rindex (const char *, int);
 
 #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)  || defined(_BSD_SOURCE)
 int ffs (int);
+int ffsl (long);
+int ffsll (long long);
 #endif
 
 int strcasecmp (const char *, const char *);
diff --git a/src/misc/ffsl.c b/src/misc/ffsl.c
new file mode 100644
index 0000000000000000000000000000000000000000..0105c66af9d18946ce9b3f8616c8baa6c7a55cde
--- /dev/null
+++ b/src/misc/ffsl.c
@@ -0,0 +1,7 @@
+#include <strings.h>
+#include "atomic.h"
+
+int ffsl(long i)
+{
+	return i ? a_ctz_l(i)+1 : 0;
+}
diff --git a/src/misc/ffsll.c b/src/misc/ffsll.c
new file mode 100644
index 0000000000000000000000000000000000000000..0c5ced826657993210a021f49d76560a03a416d6
--- /dev/null
+++ b/src/misc/ffsll.c
@@ -0,0 +1,7 @@
+#include <strings.h>
+#include "atomic.h"
+
+int ffsll(long long i)
+{
+	return i ? a_ctz_64(i)+1 : 0;
+}