__from_data16 and __from_text16 now take a pointer to a
.data16/.text16 variable, and return the real-mode offset within the
appropriate segment. This matches the use case for every occurrence
of these macros, and prevents potential future bugs such as that fixed
in commit d51d80f. (The bug arose essentially because "&pointer" is
still syntactically valid.)
the only one we actually use). This allows REAL_EXEC fragments to
contain proper references to constraints (e.g. "%w0"), rather than having
to force the use of specific registers.
Note that the "num_constraints" parameter is now completely obsolete, and
that we can probably reduce the syntax to something like
__asm__ __volatile__ ( REAL_CODE ( "asm statements" )
: output constraints
: input constraints
: clobber );
which would look much more natural, and avoid the need to always specify
a clobber list.
Add userptr_t to libkir.h, to allow it to at least compile.
Use .text16.data section with "aw" attributes, to avoid section type
conflicts when placing both code and data into .text16.
Add __from_{text16,data16}.
