On Red Hat 6.0 on the Alpha processor (kernel 2.2.3), there
seems to be an inconsistency between
the file elfcore.h (which defines elf_prstatus) and the
kernel (which dumps an elf_prstatus into
a note in the core file).

When one compiles a trivial code which prints the sizeof
(struct elf_prstatus),
one gets the result 352, however the size of the NOTE in a
core file (which is
set by the kernel to be sizeof (elf_prstatus) is 384.

The inconsistency appears to be caused by an extra 32 bytes
of something
somewhere before the pr_reg structure, since one can easily
write a program
to put known values in the registers and then core dump,
allowing one to see
where the registers appear...