Beman Dawes wrote:
I'm not sure how widespread differing endianness between ints and floats is across the various platforms.
The Wikipedia article says it's uncommon, IIRC, but we need some real data on that.
I think it's vanishingly rare and can be ignored (as can any non-ieee754 formats). The only case I'm aware of is the format of doubles on the original (20-year-old) ARM FPA chip. This would store the bytes of a double as 45670123, i.e the bytes are little-endian within the words (like ints) but the two words are ordered big endian. <anecdote>This chip was designed by 3 guys, and I shared an office with 2 of them at the time. One came from Acorn who had been using little-endian ARM chips for years, and the other came from Apple (who were about to put an ARM chip in the first Newton) and had a 68000 big-endian background. So perhaps it's not surprising that it got muddled. (The third guy designed the divide-and-square-root unit, nocturnally.) I doubt that more than a few hundred of these chips were ever made, but the format was a bit more widespread because the chip could be emulated by the OS through illegal instruction traps.</anecdote> Cheers, Phil.