diff --git a/ia64.s b/ia64.s
index 3865712266..6320922cca 100644
--- a/ia64.s
+++ b/ia64.s
@@ -7,7 +7,7 @@
 //   void *rb_ia64_bsp(void) { return __builtin_ia64_bsp(); }
 // 
 // Note that rb_ia64_flushrs and rb_ia64_bsp works in its own stack frame.
-// It's because BSP is updated by br.call/brl.call (not alloc instruction)
+// It's because BSP is updated by br.call/brl.call (not alloc instruction).
 // So rb_ia64_flushrs flushes stack frames including caller's one.
 // rb_ia64_bsp returns the address next to caller's register stack frame. 
 //