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Diffstat (limited to 'distrib/sdl-1.2.15/src/video/ataricommon/SDL_atarisuper.h')
| -rw-r--r-- | distrib/sdl-1.2.15/src/video/ataricommon/SDL_atarisuper.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/src/video/ataricommon/SDL_atarisuper.h b/distrib/sdl-1.2.15/src/video/ataricommon/SDL_atarisuper.h new file mode 100644 index 0000000..8f25c7e --- /dev/null +++ b/distrib/sdl-1.2.15/src/video/ataricommon/SDL_atarisuper.h @@ -0,0 +1,61 @@ +/* + SDL - Simple DirectMedia Layer + Copyright (C) 1997-2012 Sam Lantinga + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Sam Lantinga + slouken@libsdl.org +*/ +#include "SDL_config.h" + +#ifndef _ATARI_SUPER_h +#define _ATARI_SUPER_h + +#include "SDL_stdinc.h" + +#ifndef SuperToUser + +/* + * Safe binding to switch back from supervisor to user mode. + * On TOS or EmuTOS, if the stack pointer has changed between Super(0) + * and Super(oldssp), the resulting user stack pointer is wrong. + * This bug does not occur with FreeMiNT. + * So the safe way to return from supervisor to user mode is to backup + * the stack pointer then restore it after the trap. + * Sometimes, GCC optimizes the stack usage, so this matters. + */ +#define SuperToUser(ptr) \ +(void)__extension__ \ +({ \ + register long retvalue __asm__("d0"); \ + register long sp_backup; \ + \ + __asm__ volatile \ + ( \ + "movl sp,%1\n\t" \ + "movl %2,sp@-\n\t" \ + "movw #0x20,sp@-\n\t" \ + "trap #1\n\t" \ + "movl %1,sp\n\t" \ + : "=r"(retvalue), "=&r"(sp_backup) /* outputs */ \ + : "g"((long)(ptr)) /* inputs */ \ + : "d1", "d2", "a0", "a1", "a2" \ + ); \ +}) + +#endif /* SuperToUser */ + +#endif /* _ATARI_SUPER_h */ |