diff --git a/Modules/_decimal/libmpdec/mpdecimal.h b/Modules/_decimal/libmpdec/mpdecimal.h
index d131c71441f..e014f1c3a51 100644
--- a/Modules/_decimal/libmpdec/mpdecimal.h
+++ b/Modules/_decimal/libmpdec/mpdecimal.h
@@ -106,6 +106,11 @@ extern "C" {
   #endif
 #endif
 
+/* ASM isn't available in strict ansi C mode */
+#if defined(ASM) && defined(__STRICT_ANSI__)
+  #undef ASM
+  #define ANSI
+#endif
 
 /* BEGIN CONFIG_64 */
 #if defined(CONFIG_64)