diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index feb329f530..225946c03d 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -107,7 +107,7 @@ func (e Errno) Timeout() bool {
 	return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
 }
 
-// Implemented in asm_windows.s
+// Implemented in runtime/syscall_windows.go.
 func compileCallback(fn interface{}, cleanstack bool) uintptr
 
 // Converts a Go function to a function pointer conforming