diff --git a/libc/arch-x86/bionic/futex_x86.S b/libc/arch-x86/bionic/futex_x86.S
new file mode 100644
index 0000000..94647ca
--- /dev/null
+++ b/libc/arch-x86/bionic/futex_x86.S
@@ -0,0 +1,16 @@
+#include <private/bionic_asm.h>
+
+// int __futex_syscall4(volatile void* ftx, int op, int val, const struct timespec* timeout)
+ENTRY_PRIVATE(__futex_syscall4)
+    pushl   %ebx
+    pushl   %esi
+    movl    12(%esp), %ebx      /* ftx */
+    movl    16(%esp), %ecx      /* op */
+    movl    20(%esp), %edx      /* val */
+    movl    24(%esp), %esi      /* timeout */
+    movl    $__NR_futex, %eax
+    int     $0x80
+    popl    %esi
+    popl    %ebx
+    ret
+END(__futex_syscall4)