piet@cs.ruu.nl (Piet van Oostrum) (07/13/90)
I am still trying to get the whole scoop on bit-field alignment in the
HP-UX cc compiler on HP9000/300. I detected another case where the
bit-field was aligned, which is actually more in line with what others do -
if there were not a case that I don't understand -
struct test {
/* char p;*/
int a:14;
int b:20;
short c:5; } x;
This case (with the char p commented out) aligns b on a 2-byte boundary,
presumably because it would otherwise cross a 4-byte boundary, although
4-byte boundaries are not special in records. But if the char p is
inserted, no padding is done, the field a doesn't even start on a 2-byte
boundary. Now I don't understand what the underlying algorithm is. This
might even be a bug.
--
Piet* van Oostrum, Dept of Computer Science, Utrecht University,
Padualaan 14, P.O. Box 80.089, 3508 TB Utrecht, The Netherlands.
Telephone: +31-30-531806 Uucp: uunet!mcsun!ruuinf!piet
Telefax: +31-30-513791 Internet: piet@cs.ruu.nl (*`Pete')