/*

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

*/

/*

* VBL queue routine

*

* Patrice Mandin

*/

#define _vbl_queue 0x456

#define _hz_200 0x4ba

.text

.globl _SDL_AtariVblInstall

.globl _SDL_AtariVblUninstall

.globl _SDL_MintAudio_hasfpu

/*--- Save/restore FPU context ---*/

#if defined(__mcoldfire__)

#define SAVE_FPU_CONTEXT \

lea sp@(-216),sp; \

fsave sp@; \

fmovel fpiar,sp@-; \

lea sp@(-64),sp; \

fmovemd fp0-fp7,sp@

#define RESTORE_FPU_CONTEXT \

fmovemd sp@,fp0-fp7; \

lea sp@(64),sp; \

fmovel sp@+,fpiar; \

frestore sp@; \

lea sp@(216),sp

#else

#define SAVE_FPU_CONTEXT \

.chip 68k/68881; \

fsave sp@-; \

fmoveml fpcr/fpsr/fpiar,sp@-; \

fmovemx fp0-fp7,sp@-; \

.chip 68k

#define RESTORE_FPU_CONTEXT \

.chip 68k/68881; \

fmovemx sp@+,fp0-fp7; \

fmoveml sp@+,fpcr/fpsr/fpiar; \

frestore sp@+; \

.chip 68k

#endif

/*--- Vector installer ---*/

_SDL_AtariVblInstall:

#if defined(__mcoldfire__)

movel sp@(4),d0

movel d0,my_vector

#else

movel sp@(4),my_vector

#endif

lea _my_vbl,a0

clrw vbl_mutex

#if defined(__mcoldfire__)

movel _hz_200.w,d0

movel d0, _SDL_Atari_hz200

#else

movel _hz_200.w, _SDL_Atari_hz200

#endif

/* Stop interrupts */

movew #0x2700,sr

/* Read vbl_queue pointer */

movel _vbl_queue.w,a1

/* Search a free place */

moveq #7,d0

bcl_search_place:

movel (a1),d1

beqs place_found

addql #4,a1

#if defined(__mcoldfire__)

subql #1,d0

bpls bcl_search_place

#else

dbra d0,bcl_search_place

#endif

/* Not found */

moveq #1,d0

bras exit_vbl_queue

/* Then install ourselves */

place_found:

movel a0,(a1)

moveq #0,d0

exit_vbl_queue:

/* Restart interrupts */

movew #0x2300,sr

rts

/*--- Vector uninstaller ---*/

_SDL_AtariVblUninstall:

movel sp@(4),d0

cmpl my_vector,d0

bnes badvector

movel #_my_vbl,d0

/* Stop interrupts */

movew #0x2700,sr

/* Read vbl_queue pointer */

movel _vbl_queue.w,a1

/* Search where we are */

moveq #7,d1

bcl2_search_place:

cmpl (a1),d0

bnes next_place

clrl (a1)

moveq #0,d1

next_place:

addql #4,a1

#if defined(__mcoldfire__)

subql #1,d1

bpls bcl_search_place

#else

dbra d1,bcl2_search_place

#endif

/* Restart interrupts */

movew #0x2300,sr

badvector:

rts

/*--- Our vbl ---*/

_my_vbl:

#if defined(__mcoldfire__)

lea sp@(-60),sp

moveml d0-d7/a0-a6,sp@

#else

moveml d0-d7/a0-a6,sp@-

#endif

/* Update _hz_200 */

#if defined(__mcoldfire__)

movel _hz_200.w,d0

movel d0, _SDL_Atari_hz200

#else

movel _hz_200.w, _SDL_Atari_hz200

#endif

/* Verify if this is not already running */

tstw vbl_mutex

bnes vbl_end

#if defined(__mcoldfire__)

movew vbl_mutex,d0

notl d0

movew d0,vbl_mutex

#else

notw vbl_mutex

#endif

/* Save FPU if needed */

tstw _SDL_MintAudio_hasfpu

beqs SDL_AtariVbl_nofpu1

SAVE_FPU_CONTEXT

SDL_AtariVbl_nofpu1:

movel my_vector,a0

jsr a0@

/* Restore FPU if needed */

tstw _SDL_MintAudio_hasfpu

beqs SDL_AtariVbl_Xbios_nofpu2

RESTORE_FPU_CONTEXT

SDL_AtariVbl_Xbios_nofpu2:

clrw vbl_mutex

vbl_end:

#if defined(__mcoldfire__)

moveml sp@,d0-d7/a0-a6

lea sp@(60),sp

#else

moveml sp@+,d0-d7/a0-a6

#endif

rts

.data

.even

.comm _SDL_Atari_hz200,4*1

.even

.comm vbl_mutex,2*1

.even

.comm my_vector,4*1