1 /***************************************************************************
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
10 * Copyright (C) 2002 by Felix Arends
12 * All files in this archive are subject to the GNU General Public License.
13 * See the file COPYING in the source tree root for full license agreement.
15 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
16 * KIND, either express or implied.
18 ****************************************************************************/
22 #include <SDL_thread.h>
24 #include "system-sdl.h"
27 #include "thread-sdl.h"
31 static SDL_TimerID tick_timer_id
;
34 /* Condition to signal that "interrupts" may proceed */
35 static SDL_cond
*sim_thread_cond
;
36 /* Mutex to serialize changing levels and exclude other threads while
38 static SDL_mutex
*sim_irq_mtx
;
39 static int interrupt_level
= HIGHEST_IRQ_LEVEL
;
40 static int handlers_pending
= 0;
41 static int status_reg
= 0;
43 extern void (*tick_funcs
[MAX_NUM_TICK_TASKS
])(void);
46 * 1) All threads must pass unblocked
47 * 2) Current handler must always pass unblocked
48 * 3) Threads must be excluded when irq routine is running
49 * 4) No more than one handler routine should execute at a time
51 int set_irq_level(int level
)
53 SDL_LockMutex(sim_irq_mtx
);
55 int oldlevel
= interrupt_level
;
57 if (status_reg
== 0 && level
== 0 && oldlevel
!= 0)
59 /* Not in a handler and "interrupts" are being reenabled */
60 if (handlers_pending
> 0)
61 SDL_CondSignal(sim_thread_cond
);
64 interrupt_level
= level
; /* save new level */
66 SDL_UnlockMutex(sim_irq_mtx
);
70 void sim_enter_irq_handler(void)
72 SDL_LockMutex(sim_irq_mtx
);
75 if(interrupt_level
!= 0)
77 /* "Interrupts" are disabled. Wait for reenable */
78 SDL_CondWait(sim_thread_cond
, sim_irq_mtx
);
84 void sim_exit_irq_handler(void)
86 if (--handlers_pending
> 0)
87 SDL_CondSignal(sim_thread_cond
);
90 SDL_UnlockMutex(sim_irq_mtx
);
93 bool sim_kernel_init(void)
95 sim_irq_mtx
= SDL_CreateMutex();
96 if (sim_irq_mtx
== NULL
)
98 fprintf(stderr
, "Cannot create sim_handler_mtx\n");
102 sim_thread_cond
= SDL_CreateCond();
103 if (sim_thread_cond
== NULL
)
105 fprintf(stderr
, "Cannot create sim_thread_cond\n");
112 void sim_kernel_shutdown(void)
114 SDL_RemoveTimer(tick_timer_id
);
115 SDL_DestroyMutex(sim_irq_mtx
);
116 SDL_DestroyCond(sim_thread_cond
);
119 Uint32
tick_timer(Uint32 interval
, void *param
)
126 new_tick
= (SDL_GetTicks() - start_tick
) / (1000/HZ
);
128 if(new_tick
!= current_tick
)
131 for(t
= new_tick
- current_tick
; t
> 0; t
--)
135 sim_enter_irq_handler();
137 /* Run through the list of tick tasks */
138 for(i
= 0;i
< MAX_NUM_TICK_TASKS
;i
++)
146 sim_exit_irq_handler();
149 current_tick
= new_tick
;
155 void tick_start(unsigned int interval_in_ms
)
157 if (tick_timer_id
!= NULL
)
159 SDL_RemoveTimer(tick_timer_id
);
160 tick_timer_id
= NULL
;
164 start_tick
= SDL_GetTicks();
167 tick_timer_id
= SDL_AddTimer(interval_in_ms
, tick_timer
, NULL
);