[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: USE_LSB_TAG and MS-DOS
From: |
Stefan Monnier |
Subject: |
Re: USE_LSB_TAG and MS-DOS |
Date: |
17 May 2004 12:22:15 -0400 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 |
>> Can you compile with ENABLE_CHECKING and try again?
>> And give me a backtrace?
> Will try to do that soon.
> By ``backtrace'' you meant a C-level backtrace inside GDB, yes?
Yes.
>> After all, all we need is to make sure pointers are multiples of 8.
>> GNU malloc guarantees that AFAIK for malloced objects and DECL_ALIGN allows
>> to get the same guarantee for static objects, so if we have both the only
>> reasonf ro USE_LSB_TAG to fail is a bug, right?
> Perhaps so, but, being unsure I know enough about the alignment
> issues, I bother. For example, is stack alignment an issue?
It shouldn't. The only places where I change the alignemnt are where I use
DECL_ALIGN and in pure_alloc. In both cases the alignment should be
increased ather than decreased, so it shouldn't cause any problem.
Barring any bug, that is (of course).
> And what about the default alignment used by GCC for code and data?
> I also need to check whether the __attribute__((__align__)) thingy is
> supported and does TRT in the DJGPP (a.k.a. MS-DOS) port of GCC.
ENABLE_CHECKING should give you those answers pretty quickly since it
checks that pointers are properly aligned before tagging them to make
Lisp_Objects.
> There was also talk about using memalign. I didn't follow that thread
> closely, so I don't remember: is that relevant in any way to the case
> in point?
No, the code is currently not using memalign. The use of memalign would
only be for cases where malloc is not known to return
multiple-of-8 pointers.
Stefan
Re: USE_LSB_TAG and MS-DOS, Stefan Monnier, 2004/05/16
- Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/17
- Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/18
- Re: USE_LSB_TAG and MS-DOS, Andreas Schwab, 2004/05/18
- Re: USE_LSB_TAG and MS-DOS, Stefan Monnier, 2004/05/18
- Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/18
- Re: USE_LSB_TAG and MS-DOS, Stefan Monnier, 2004/05/18
- Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/19
- Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/20
Re: USE_LSB_TAG and MS-DOS, Eli Zaretskii, 2004/05/18