diff --git a/abstract-machine/klib/include/klib-macros.h b/abstract-machine/klib/include/klib-macros.h
index 7789f86..3e6fb67 100644
--- a/abstract-machine/klib/include/klib-macros.h
+++ b/abstract-machine/klib/include/klib-macros.h
@@ -16,7 +16,7 @@
   ({ for (const char *p = s; *p; p++) putch(*p); })
 
 #define io_read(reg) \
-  ({ volatile reg##_T __io_param; \
+  ({ static reg##_T __io_param; \
     ioe_read(reg, (void*)&__io_param); \
     __io_param; })