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Diffstat (limited to 'firmware/target/hosted/sdl/kernel-sdl.c')
-rw-r--r--firmware/target/hosted/sdl/kernel-sdl.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/firmware/target/hosted/sdl/kernel-sdl.c b/firmware/target/hosted/sdl/kernel-sdl.c
new file mode 100644
index 0000000000..d796921e35
--- /dev/null
+++ b/firmware/target/hosted/sdl/kernel-sdl.c
@@ -0,0 +1,162 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2002 by Felix Arends
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <SDL.h>
+#include <SDL_thread.h>
+#include "memory.h"
+#include "system-sdl.h"
+#include "thread-sdl.h"
+#include "kernel.h"
+#include "thread.h"
+#include "panic.h"
+#include "debug.h"
+
+static SDL_TimerID tick_timer_id;
+long start_tick;
+
+/* Condition to signal that "interrupts" may proceed */
+static SDL_cond *sim_thread_cond;
+/* Mutex to serialize changing levels and exclude other threads while
+ * inside a handler */
+static SDL_mutex *sim_irq_mtx;
+static int interrupt_level = HIGHEST_IRQ_LEVEL;
+static int handlers_pending = 0;
+static int status_reg = 0;
+
+/* Nescessary logic:
+ * 1) All threads must pass unblocked
+ * 2) Current handler must always pass unblocked
+ * 3) Threads must be excluded when irq routine is running
+ * 4) No more than one handler routine should execute at a time
+ */
+int set_irq_level(int level)
+{
+ SDL_LockMutex(sim_irq_mtx);
+
+ int oldlevel = interrupt_level;
+
+ if (status_reg == 0 && level == 0 && oldlevel != 0)
+ {
+ /* Not in a handler and "interrupts" are being reenabled */
+ if (handlers_pending > 0)
+ SDL_CondSignal(sim_thread_cond);
+ }
+
+ interrupt_level = level; /* save new level */
+
+ SDL_UnlockMutex(sim_irq_mtx);
+ return oldlevel;
+}
+
+void sim_enter_irq_handler(void)
+{
+ SDL_LockMutex(sim_irq_mtx);
+ handlers_pending++;
+
+ if(interrupt_level != 0)
+ {
+ /* "Interrupts" are disabled. Wait for reenable */
+ SDL_CondWait(sim_thread_cond, sim_irq_mtx);
+ }
+
+ status_reg = 1;
+}
+
+void sim_exit_irq_handler(void)
+{
+ if (--handlers_pending > 0)
+ SDL_CondSignal(sim_thread_cond);
+
+ status_reg = 0;
+ SDL_UnlockMutex(sim_irq_mtx);
+}
+
+static bool sim_kernel_init(void)
+{
+ sim_irq_mtx = SDL_CreateMutex();
+ if (sim_irq_mtx == NULL)
+ {
+ panicf("Cannot create sim_handler_mtx\n");
+ return false;
+ }
+
+ sim_thread_cond = SDL_CreateCond();
+ if (sim_thread_cond == NULL)
+ {
+ panicf("Cannot create sim_thread_cond\n");
+ return false;
+ }
+
+ return true;
+}
+
+void sim_kernel_shutdown(void)
+{
+ SDL_RemoveTimer(tick_timer_id);
+ SDL_DestroyMutex(sim_irq_mtx);
+ SDL_DestroyCond(sim_thread_cond);
+}
+
+Uint32 tick_timer(Uint32 interval, void *param)
+{
+ long new_tick;
+
+ (void) interval;
+ (void) param;
+
+ new_tick = (SDL_GetTicks() - start_tick) / (1000/HZ);
+
+ while(new_tick != current_tick)
+ {
+ sim_enter_irq_handler();
+
+ /* Run through the list of tick tasks - increments tick
+ * on each iteration. */
+ call_tick_tasks();
+
+ sim_exit_irq_handler();
+ }
+
+ return 1;
+}
+
+void tick_start(unsigned int interval_in_ms)
+{
+ if (!sim_kernel_init())
+ {
+ panicf("Could not initialize kernel!");
+ exit(-1);
+ }
+
+ if (tick_timer_id != NULL)
+ {
+ SDL_RemoveTimer(tick_timer_id);
+ tick_timer_id = NULL;
+ }
+ else
+ {
+ start_tick = SDL_GetTicks();
+ }
+
+ tick_timer_id = SDL_AddTimer(interval_in_ms, tick_timer, NULL);
+}