Eric Botcazou <ebotca...@adacore.com> writes: >> What's the main potential problem you see? The backwards condition: >> >> (fieldmode == BLKmode ? BYTES_BIG_ENDIAN : WORDS_BIG_ENDIAN) >> >> should apply the same bit-for-bit mapping between source and target >> as the patch applies. > > Not if the objects don't have the same size.
Ugh. > In Ada we have BLKmode bitfields, i.e. fields whose type has BLKmode > and whose DECL_SIZE is smaller than the TYPE_SIZE of the type; in this > case, we want to drop the rightmost bytes in memory order, whatever > the endianness. OK, I see how the two are different now, but I still don't get why the current version is right. If we say words are 16 bits for simplicity, and we're storing VALUE == 0x0001_2345 into a 3-byte BLKmode bitfield, surely we want to store 0x01_2345 rather than 0x00_0123? It seems odd for fieldmode (which I thought was a property of the target) to affect the interpretation of VALUE (the source). Richard
