From: Alain Frisch <alain@frisch.fr>
To: Dmitry Bely <dmitry.bely@gmail.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Compiler bug?
Date: Mon, 06 Aug 2012 13:32:26 +0200 [thread overview]
Message-ID: <501FAB4A.107@frisch.fr> (raw)
In-Reply-To: <CAMT7qiR=7LS3211gkA2HOVwB+BQj81cs1efjy3eBESgqW03s5g@mail.gmail.com>
On 08/06/2012 01:03 PM, Dmitry Bely wrote:
> _caml_call_gc:
> ; Record lowest stack address and return address
> mov eax, [esp]
> mov _caml_last_return_address, eax
> lea eax, [esp+4]
> mov _caml_bottom_of_stack, eax
> ; Save all regs used by the code generator
> L105: push ebp
> push edi
> push esi
> push edx
> push ecx
> push ebx
> push eax
> mov _caml_gc_regs, esp
> ; Call the garbage collector
> call _caml_garbage_collection
> ; Restore all regs used by the code generator
> pop eax
> pop ebx
> pop ecx
> pop edx
> pop esi
> pop edi
> pop ebp
> ; Return to caller
> ret
>
> it preserves registers and so it cannot update them
No, this code does not preserves registers. It stores them on the
stack, pass a pointer to them to the C code (in caml_gc_regs), and then
restore their values from the stack. In between, the C code has updated
the values on the stack, so the restored values are not the saved ones.
-- Alain
next prev parent reply other threads:[~2012-08-06 11:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-06 10:04 Dmitry Bely
2012-08-06 10:11 ` Alain Frisch
2012-08-06 10:20 ` Dmitry Bely
2012-08-06 10:34 ` Alain Frisch
2012-08-06 11:03 ` Dmitry Bely
2012-08-06 11:32 ` Alain Frisch [this message]
2012-08-06 12:16 ` Dmitry Bely
2012-08-07 1:35 ` Cedric Cellier
2012-08-08 16:03 ` Dmitry Bely
2012-08-08 18:03 ` Alain Frisch
2012-08-08 18:22 ` Jesper Louis Andersen
2012-08-08 18:40 ` Dmitry Bely
2012-08-08 19:29 ` Fabrice Le Fessant
2012-08-08 23:34 ` Anil Madhavapeddy
2012-08-09 0:53 ` Francois Berenger
-- strict thread matches above, loose matches on Subject: below --
2006-05-17 23:14 compiler bug? Dan Koppel
2006-05-17 23:33 ` [Caml-list] " John Carr
2006-05-18 17:15 ` Xavier Leroy
2006-05-18 17:34 ` Jacques Carette
2006-05-18 17:46 ` Xavier Leroy
2006-05-18 19:31 ` Jacques Carette
2006-05-18 20:07 ` David Brown
2006-05-18 20:15 ` Jacques Carette
2006-05-18 20:20 ` Alain Frisch
2006-05-18 18:19 ` skaller
2006-05-18 18:53 ` Jacques Carette
2006-05-19 1:47 ` skaller
2006-05-19 2:17 ` Brian Hurt
2006-05-19 3:11 ` skaller
2006-05-19 16:48 ` Jacques Carette
2006-05-19 19:10 ` skaller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=501FAB4A.107@frisch.fr \
--to=alain@frisch.fr \
--cc=caml-list@inria.fr \
--cc=dmitry.bely@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).