/
SDL_vbltimer.S
133 lines (99 loc) · 2.32 KB
/
SDL_vbltimer.S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
slouken@libsdl.org
*/
#ifdef SAVE_RCSID
static char rcsid =
"@(#) $Id$";
#endif
/*
* VBL queue routine
*
* Patrice Mandin
*/
#define _vbl_queue 0x456
.text
.globl _SDL_AtariVblInstall
.globl _SDL_AtariVblUninstall
/*--- Vector installer ---*/
_SDL_AtariVblInstall:
movel sp@(4),my_vector
lea _my_vbl,a0
clrw vbl_mutex
/* 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
dbra d0,bcl_search_place
/* 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
dbra d1,bcl2_search_place
/* Restart interrupts */
movew #0x2300,sr
badvector:
rts
/*--- Our vbl ---*/
_my_vbl:
/* Verify if this is not already running */
tstw vbl_mutex
bnes vbl_end
notw vbl_mutex
moveml d0-d7/a0-a6,sp@-
movel my_vector,a0
jsr a0@
moveml sp@+,d0-d7/a0-a6
clrw vbl_mutex
vbl_end:
rts
.data
.even
.comm vbl_mutex,2*1
.even
.comm my_vector,4*1