>I’d need to think a bit more to come up with a signed version. Invert the high bits, turning two's complement into biased format (0 = lowest negative number,

>I’d need to think a bit more to come up with a signed version. Invert the high bits, turning two's complement into biased format (0 = lowest negative number, 0xFF...F = highest positive number). Then do the add+rotate and convert the result back.