-
Show log
Commit
-
Hash : 36998b82
Author :
Date : 2017-07-20T10:48:57
Fixed bug 3689 - MMX YUV renderer crash felix The functions in src/render/SDL_yuv_mmx.c contain the following inline assembly snippet: /* tap dance to workaround the inability to use %%ebx at will... */ /* move one thing to the stack... */ "pushl $0\n" /* save a slot on the stack. */ "pushl %%ebx\n" /* save %%ebx. */ "movl %0, %%ebx\n" /* put the thing in ebx. */ "movl %%ebx,4(%%esp)\n" /* put the thing in the stack slot. */ "popl %%ebx\n" /* get back %%ebx (the PIC register). */ Here's how it ended up in a binary on my old laptop: 0xb5c17dbd <ColorRGBDitherYV12MMX1X+93>: push $0x0 0xb5c17dbf <ColorRGBDitherYV12MMX1X+95>: push %ebx 0xb5c17dc0 <ColorRGBDitherYV12MMX1X+96>: mov 0xc(%esp),%ebx 0xb5c17dc4 <ColorRGBDitherYV12MMX1X+100>: mov %ebx,0x4(%esp) 0xb5c17dc8 <ColorRGBDitherYV12MMX1X+104>: pop %ebx Apparently the compiler, oblivious to the fact that the assembly snippet manipulates the %esp register, decided to refer to the operand via that same register instead of via %ebp (I believe -fomit-frame-pointer enables this). This causes %ebx to be loaded with the wrong value, which later leads to a null pointer dereference. Recent GCC can use the %ebx register normally: <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602#c16>. There is even an explicit constraint "b" for allocating it.
-
Files
- .hgignore
- Android.mk
- BUGS.txt
- CMakeLists.txt
- COPYING.txt
- CREDITS.txt
- INSTALL.txt
- Makefile.in
- Makefile.minimal
- Makefile.pandora
- Makefile.psp
- Makefile.wiz
- README-SDL.txt
- README.txt
- SDL2.spec.in
- TODO.txt
- VisualC-WinRT/
- VisualC.html
- VisualC/
- WhatsNew.txt
- Xcode-iOS/
- Xcode/
- acinclude/
- android-project/
- autogen.sh
- build-scripts/
- cmake/
- cmake_uninstall.cmake.in
- configure
- configure.in
- debian/
- docs/
- include/
- sdl2-config.cmake.in
- sdl2-config.in
- sdl2.m4
- sdl2.pc.in
- src/
- test/
- visualtest/
-
Properties
-
Git HTTP https://git.kmx.io/kc3-lang/SDL.git Git SSH git@git.kmx.io:kc3-lang/SDL.git Public access ? public Description Users
Tags
-
README.txt
-
Simple DirectMedia Layer (SDL) Version 2.0 --- https://www.libsdl.org/ Simple DirectMedia Layer is a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware via OpenGL and Direct3D. It is used by video playback software, emulators, and popular games including Valve's award winning catalog and many Humble Bundle games. More extensive documentation is available in the docs directory, starting with README.md Enjoy! Sam Lantinga (slouken@libsdl.org)