+#define BCO_NEXT_32 (bciPtr += 2, (((StgWord) instrs[bciPtr-2]) << 16) + ((StgWord) instrs[bciPtr-1]))
+#define BCO_NEXT_64 (bciPtr += 4, (((StgWord) instrs[bciPtr-4]) << 48) + (((StgWord) instrs[bciPtr-3]) << 32) + (((StgWord) instrs[bciPtr-2]) << 16) + ((StgWord) instrs[bciPtr-1]))
+#if WORD_SIZE_IN_BITS == 32
+#define BCO_NEXT_WORD BCO_NEXT_32
+#elif WORD_SIZE_IN_BITS == 64
+#define BCO_NEXT_WORD BCO_NEXT_64
+#else
+#error Cannot cope with WORD_SIZE_IN_BITS being nether 32 nor 64
+#endif
+#define BCO_GET_LARGE_ARG ((bci & bci_FLAG_LARGE_ARGS) ? BCO_NEXT_WORD : BCO_NEXT)
+