diff --git a/src/libthread/Linuxasm.s b/src/libthread/Linuxasm.s
new file mode 100644
index 0000000..197f12b
--- /dev/null
+++ b/src/libthread/Linuxasm.s
@@ -0,0 +1,7 @@
+.globl _tas
+_tas:
+	movl $0xCAFEBABE, %eax
+	movl 4(%esp), %ecx
+	xchgl %eax, 0(%ecx)
+	ret
+