summaryrefslogtreecommitdiffstats
path: root/uisimulator/sdl/thread-sdl.c
blob: aac8e2fbb93ade1c8e9812a85df40644ab6a7612 (plain)
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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2006 Dan Everton
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <time.h>
#include <SDL.h>
#include <SDL_thread.h>
#include <stdlib.h>
#include <memory.h>
#include "thread-sdl.h"
#include "kernel.h"
#include "thread.h"
#include "debug.h"

/* Define this as 1 to show informational messages that are not errors. */
#define THREAD_SDL_DEBUGF_ENABLED 0

#if THREAD_SDL_DEBUGF_ENABLED
#define THREAD_SDL_DEBUGF(...) DEBUGF(__VA_ARGS__)
static char __name[32];
#define THREAD_SDL_GET_NAME(thread) \
    ({ thread_get_name(__name, sizeof(__name)/sizeof(__name[0]), thread); __name; })
#else
#define THREAD_SDL_DEBUGF(...)
#define THREAD_SDL_GET_NAME(thread)
#endif

#define THREAD_PANICF(str...) \
    ({ fprintf(stderr, str); exit(-1); })

struct thread_entry threads[MAXTHREADS];            /* Thread entries as in core */
static SDL_mutex *m;
static SDL_sem *s;
static struct thread_entry *running;

void kill_sim_threads(void)
{
    int i;
    SDL_LockMutex(m);
    for (i = 0; i < MAXTHREADS; i++)
    {
        struct thread_entry *thread = &threads[i];
        if (thread->context.t != NULL)
        {
            SDL_LockMutex(m);
            if (thread->statearg == STATE_RUNNING)
                SDL_SemPost(s);
            else
                SDL_CondSignal(thread->context.c);
            SDL_KillThread(thread->context.t);
            SDL_DestroyCond(thread->context.c);
        }
    }
    SDL_DestroyMutex(m);
    SDL_DestroySemaphore(s);
}

static int find_empty_thread_slot(void)
{
    int n;

    for (n = 0; n < MAXTHREADS; n++)
    {
        if (threads[n].name == NULL)
            break;
    }

    return n;
}

static void add_to_list(struct thread_entry **list,
                        struct thread_entry *thread)
{
    if (*list == NULL)
    {
        /* Insert into unoccupied list */
        thread->next = thread;
        thread->prev = thread;
        *list = thread;
    }
    else
    {
        /* Insert last */
        thread->next = *list;
        thread->prev = (*list)->prev;
        thread->prev->next = thread;
        (*list)->prev = thread;
    }
}

static void remove_from_list(struct thread_entry **list,
                             struct thread_entry *thread)
{
    if (thread == thread->next)
    {
        /* The only item */
        *list = NULL;
        return;
    }

    if (thread == *list)
    {
        /* List becomes next item */
        *list = thread->next;
    }

    /* Fix links to jump over the removed entry. */
    thread->prev->next = thread->next;
    thread->next->prev = thread->prev;
}

struct thread_entry *thread_get_current(void)
{
    return running;
}

void switch_thread(bool save_context, struct thread_entry **blocked_list)
{
    struct thread_entry *current = running;

    SDL_UnlockMutex(m);

    SDL_SemWait(s);

    SDL_LockMutex(m);
    running = current;

    SDL_SemPost(s);

    (void)save_context; (void)blocked_list;
}

void sleep_thread(int ticks)
{
    struct thread_entry *current;

    current = running;
    current->statearg = STATE_SLEEPING;

    SDL_CondWaitTimeout(current->context.c, m, (1000/HZ) * ticks + (500/HZ));
    running = current;

    current->statearg = STATE_RUNNING;
}

int runthread(void *data)
{
    struct thread_entry *current;

    /* Cannot access thread variables before locking the mutex as the
       data structures may not be filled-in yet. */
    SDL_LockMutex(m);
    running = (struct thread_entry *)data;
    current = running;
    current->context.start();

    THREAD_SDL_DEBUGF("Thread Done: %d (%s)\n",
                      current - threads, THREAD_SDL_GET_NAME(current));
    remove_thread(NULL);
    return 0;
}

struct thread_entry* 
    create_thread(void (*function)(void), void* stack, int stack_size,
                  const char *name)
{
    /** Avoid compiler warnings */
    SDL_Thread* t;
    SDL_cond *cond;
    int slot;

    THREAD_SDL_DEBUGF("Creating thread: (%s)\n", name ? name : "");

    slot = find_empty_thread_slot();
    if (slot >= MAXTHREADS)
    {
        DEBUGF("Failed to find thread slot\n");
        return NULL;
    }

    cond = SDL_CreateCond();
    if (cond == NULL)
    {
        DEBUGF("Failed to create condition variable\n");
        return NULL;
    }

    t = SDL_CreateThread(runthread, &threads[slot]);
    if (t == NULL)
    {
        DEBUGF("Failed to create SDL thread\n");
        SDL_DestroyCond(cond);
        return NULL;
    }

    threads[slot].stack = stack;
    threads[slot].stack_size = stack_size;
    threads[slot].name = name;
    threads[slot].statearg = STATE_RUNNING;
    threads[slot].context.start = function;
    threads[slot].context.t = t;
    threads[slot].context.c = cond;

    THREAD_SDL_DEBUGF("New Thread: %d (%s)\n",
                      slot, THREAD_SDL_GET_NAME(&threads[slot]));

    return &threads[slot];
}

void block_thread(struct thread_entry **list)
{
    struct thread_entry *thread = running;

    thread->statearg = STATE_BLOCKED;
    add_to_list(list, thread);

    SDL_CondWait(thread->context.c, m);
    running = thread;
}

void block_thread_w_tmo(struct thread_entry **list, int ticks)
{
    struct thread_entry *thread = running;

    thread->statearg = STATE_BLOCKED_W_TMO;
    add_to_list(list, thread);

    SDL_CondWaitTimeout(thread->context.c, m, (1000/HZ) * ticks);
    running = thread;

    if (thread->statearg == STATE_BLOCKED_W_TMO)
    {
        /* Timed out */
        remove_from_list(list, thread);
        thread->statearg = STATE_RUNNING;
    }
}

void wakeup_thread(struct thread_entry **list)
{
    struct thread_entry *thread = *list;

    if (thread == NULL)
    {
        return;
    }

    switch (thread->statearg)
    {
    case STATE_BLOCKED:
    case STATE_BLOCKED_W_TMO:
        remove_from_list(list, thread);
        thread->statearg = STATE_RUNNING;
        SDL_CondSignal(thread->context.c);
        break;
    }
}

void init_threads(void)
{
    int slot;

    m = SDL_CreateMutex();
    s = SDL_CreateSemaphore(0);

    memset(threads, 0, sizeof(threads));

    slot = find_empty_thread_slot();
    if (slot >= MAXTHREADS)
    {
        THREAD_PANICF("Couldn't find slot for main thread.\n");
    }

    threads[slot].stack = "       ";
    threads[slot].stack_size = 8;
    threads[slot].name = "main";
    threads[slot].statearg = STATE_RUNNING;
    threads[slot].context.t = gui_thread;
    threads[slot].context.c = SDL_CreateCond();

    running = &threads[slot];

    THREAD_SDL_DEBUGF("First Thread: %d (%s)\n",
            slot, THREAD_SDL_GET_NAME(&threads[slot]));

    if (SDL_LockMutex(m) == -1) {
        THREAD_PANICF("Couldn't lock mutex\n");
    }

    if (SDL_SemPost(s) == -1) {
        THREAD_PANICF("Couldn't post to semaphore\n");
    }
}

void remove_thread(struct thread_entry *thread)
{
    struct thread_entry *current = running;
    SDL_Thread *t;
    SDL_cond *c;

    if (thread == NULL)
    {
        thread = current;
    }

    t = thread->context.t;
    c = thread->context.c;
    thread->context.t = NULL;

    if (thread != current)
    {
        if (thread->statearg == STATE_RUNNING)
            SDL_SemPost(s);
        else
            SDL_CondSignal(c);
    }

    THREAD_SDL_DEBUGF("Removing thread: %d (%s)\n",
        thread - threads, THREAD_SDL_GET_NAME(thread));

    thread->name = NULL;

    SDL_DestroyCond(c);

    if (thread == current)
    {
        SDL_UnlockMutex(m);
    }

    SDL_KillThread(t);
}

int thread_stack_usage(const struct thread_entry *thread)
{
    return 50;
    (void)thread;
}

int thread_get_status(const struct thread_entry *thread)
{
    return thread->statearg;
}

/* Return name if one or ID if none */
void thread_get_name(char *buffer, int size,
                     struct thread_entry *thread)
{
    if (size <= 0)
        return;

    *buffer = '\0';

    if (thread)
    {
        /* Display thread name if one or ID if none */
        bool named = thread->name && *thread->name;
        const char *fmt = named ? "%s" : "%08lX";
        intptr_t name = named ?
            (intptr_t)thread->name : (intptr_t)thread;
        snprintf(buffer, size, fmt, name);
    }
}