# HG changeset patch
# User Ryan C. Gordon <icculus@icculus.org>
# Date 1202145776 0
# Node ID be12463f31ea7b709a271012abc4a1485af1d1a4
# Parent  8797fa6e2fb27dd3cf9861511bdc4f8c21bc98bd
Date: Sat, 2 Feb 2008 22:08:05 +0100
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

diff -r 8797fa6e2fb2 -r be12463f31ea include/SDL_stdinc.h
--- a/include/SDL_stdinc.h	Fri Jan 25 05:48:08 2008 +0000
+++ b/include/SDL_stdinc.h	Mon Feb 04 17:22:56 2008 +0000
@@ -331,6 +331,7 @@
 	__asm__ __volatile__ (				\
 		"std\n\t"				\
 		"rep ; movsl\n\t"			\
+		"cld\n\t"				\
 		: "=&c" (u0), "=&D" (u1), "=&S" (u2)	\
 		: "0" (n >> 2),				\
 		  "1" (dstp+(n-4)), "2" (srcp+(n-4))	\