diff --git a/libc/Makefile b/libc/Makefile
index 25d5ead8..72aef646 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -98,6 +98,9 @@ stdlib/strtof.o \
 stdlib/strtold.o \
 stdlib/wcstombs.o \
 stdlib/wctomb.o \
+string/ffsll.o \
+string/ffsl.o \
+string/ffs.o \
 string/memccpy.o \
 string/memchr.o \
 string/memcmp.o \
diff --git a/libc/include/string.h b/libc/include/string.h
index 7fa8f901..057926b0 100644
--- a/libc/include/string.h
+++ b/libc/include/string.h
@@ -34,6 +34,9 @@ __BEGIN_DECLS
 @include(size_t.h)
 @include(locale_t.h)
 
+int ffs(int);
+int ffsl(long int);
+int ffsll(long long int);
 void* memccpy(void* __restrict, const void* __restrict, int, size_t);
 void* memchr(const void*, int, size_t);
 int memcmp(const void*, const void*, size_t);
diff --git a/libc/string/ffs.cpp b/libc/string/ffs.cpp
new file mode 100644
index 00000000..84b11519
--- /dev/null
+++ b/libc/string/ffs.cpp
@@ -0,0 +1,30 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    string/ffs.cpp
+    Returns the index of the first set bit.
+
+*******************************************************************************/
+
+#include <string.h>
+
+extern "C" int ffs(int val)
+{
+	return __builtin_ffs(val);
+}
diff --git a/libc/string/ffsl.cpp b/libc/string/ffsl.cpp
new file mode 100644
index 00000000..35d8173d
--- /dev/null
+++ b/libc/string/ffsl.cpp
@@ -0,0 +1,30 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    string/ffsl.cpp
+    Returns the index of the first set bit.
+
+*******************************************************************************/
+
+#include <string.h>
+
+extern "C" int ffsl(long int val)
+{
+	return __builtin_ffsl(val);
+}
diff --git a/libc/string/ffsll.cpp b/libc/string/ffsll.cpp
new file mode 100644
index 00000000..30661ea9
--- /dev/null
+++ b/libc/string/ffsll.cpp
@@ -0,0 +1,30 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    string/ffsll.cpp
+    Returns the index of the first set bit.
+
+*******************************************************************************/
+
+#include <string.h>
+
+extern "C" int ffsll(long long int val)
+{
+	return __builtin_ffsll(val);
+}