diff --git a/libc/arch-x86/syscalls.mk b/libc/arch-x86/syscalls.mk
index 70e6e39..b6a1e38 100644
--- a/libc/arch-x86/syscalls.mk
+++ b/libc/arch-x86/syscalls.mk
@@ -24,6 +24,7 @@
 syscall_src += arch-x86/syscalls/__rt_sigtimedwait.S
 syscall_src += arch-x86/syscalls/__sched_getaffinity.S
 syscall_src += arch-x86/syscalls/__set_thread_area.S
+syscall_src += arch-x86/syscalls/__set_tid_address.S
 syscall_src += arch-x86/syscalls/__sigaction.S
 syscall_src += arch-x86/syscalls/__statfs64.S
 syscall_src += arch-x86/syscalls/__syslog.S
diff --git a/libc/arch-x86/syscalls/__set_tid_address.S b/libc/arch-x86/syscalls/__set_tid_address.S
new file mode 100644
index 0000000..0c66d47
--- /dev/null
+++ b/libc/arch-x86/syscalls/__set_tid_address.S
@@ -0,0 +1,20 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__set_tid_address)
+    pushl   %ebx
+    mov     8(%esp), %ebx
+    movl    $__NR_set_tid_address, %eax
+    int     $0x80
+    cmpl    $-MAX_ERRNO, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %ebx
+    ret
+END(__set_tid_address)