diff --git a/src/m_cond.h b/src/m_cond.h
index d4c3e116b..56dad9d2e 100644
--- a/src/m_cond.h
+++ b/src/m_cond.h
@@ -185,7 +185,8 @@ const char *M_GetExtraEmblemPatch(extraemblem_t *em, boolean big);
 UINT8 M_GotEnoughEmblems(INT32 number);
 UINT8 M_GotLowEnoughTime(INT32 tictime);
 
-#define M_Achieved(a) ((a) >= MAXCONDITIONSETS || conditionSets[a].achieved)
+//                     vvvvvvvvvv anti-integer promotion, do not remove
+#define M_Achieved(a) ((unsigned)(a) >= MAXCONDITIONSETS || conditionSets[a].achieved)
 
 #ifdef __cplusplus
 } // extern "C"