From: Marcus von Appen
To: sdl@lists.libsdl.org
Subject: [SDL] [Patch] SDL-1.2 SDL_revcpy() asm patch for the cld flag
Hi,
as reported through the FreeBSD bug tracking system in SDL 1.2.13 (and
in the 1.2 branch, if I see that correctly) the SDL_revcpy() macro sets
the direction flag (std), but does not clear it afterwards (cld), which
is wrong according to the GCC and SYS V specs. This can cause some
weird side effects, which in turn can lead to memory corruption.
You can read the full report with a detailed description and test
program at http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/120052
Attached is the submitted patch, which fixes the issue.
Regards
Marcus
--HG--
branch : SDL-1.2
processor they ship (and thus, it's likely to beat our code on PowerPC and
Intel and whatever variants or new archs show up later).
--HG--
branch : SDL-1.2
The current SVN trunk is missing the SDLCALL specifier at numerous locations.
It has to be added for all (possibly user provided) callbacks.
I stumbled over this while creating a makefile for the OpenWatcom compiler for
Win32.
[I'm fixing this for the public headers, but I'm not going to bother for the SDL library code (yet)]
To clarify: Normaly, GCC (or, to be precise, the preprocessor) will ignore
this, and compile the code happily. However, one can specify -Wundef to get a
warning about this.
One can probably argue whether to consider this a bug or not; but I think that
(a) from a semantic point of view, using "#if FOO" when FOO is not defined is
strange, and (b) since it is possible to trigger a warning about this, and a
trivial fix exists, it should be corrected.
I can think of two alternative patches, BTW:
1) Simply use #define HAVE_FOO 0, instead of not defining HAVE_FOO at all
2) Change
#if HAVE_FOO
to
#if HAVE_FOO+0
which always does the right thing.
But I think I still prefer the attached patch :-).
