-#define mutArrPtrsCardWords(n) \
- ROUNDUP_BYTES_TO_WDS(((n) + (1 << MUT_ARR_PTRS_CARD_BITS) - 1) >> MUT_ARR_PTRS_CARD_BITS)
+#define mutArrCardMask ((1 << MUT_ARR_PTRS_CARD_BITS) - 1)
+#define mutArrPtrCardDown(i) ((i) >> MUT_ARR_PTRS_CARD_BITS)
+#define mutArrPtrCardUp(i) (((i) + mutArrCardMask) >> MUT_ARR_PTRS_CARD_BITS)
+#define mutArrPtrsCardWords(n) ROUNDUP_BYTES_TO_WDS(mutArrPtrCardUp(n))