| /* |
| 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 */ |
