On 05/29/14 13:19, Yufeng Zhang wrote:
Hi Martin,
On 05/29/14 13:00, Martin Storsjo wrote:
The syntax described, including a leading '#', was not supported
in practice. (For :lo12: it is optional.)
I believe this is an issue in the parser; '#' should be optional in
either case.
It looks like gas/config/tc-aarch64.c:parse_adrp () is missing the
skip_past_char (&p, '#') at its beginning; see parse_half () for an
example.
After spending some time this afternoon reading ARMv8 Architecture Reference
Manual (ARMARM) and having a discussion with a colleague, I think I'll have
to take back what I just said. Sorry!
The A64 assembly language allows the optional # character to introduce
constant immediate operands, e.g. in LDR instructions with immediate offset:
LDR <Wt>, [<Xn|SP>], #<simm>
and in the bitfield move instructions:
BFM <Wd>, <Wn>, #<immr>, #<imms>
The ADRP instruction, however, has the following syntax:
ADRP <Xd>, <label>
whose second operand is a program label whose 4KB page address is to be
calculated, and for such a operand, it doesn't make much sense to allow the #
character as an optional prefix, e.g. ADRP X0, #foo would look weird and
confusing.
So I think your original patch is the right one to go with, and my only
comment is to remove both # characters from the line of
"
@samp{#:pg_hi21:} and @samp{#:lo12:} respectively.
"
Apologize again for the previous wrong direction.
Please get an approval from Marcus.