X-Git-Url: https://git.gag.com/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcore%2Fao_task.c;fp=src%2Fcore%2Fao_task.c;h=f5850fa4c15bab07b88fcd6c4a191ffd33323762;hb=9513be7f9d3d0b0ec29f6487fa9dc8f1ac24d0de;hp=0000000000000000000000000000000000000000;hpb=3bfe8df44b575ca430ffaa051e20faa955a06c03;p=fw%2Faltos

diff --git a/src/core/ao_task.c b/src/core/ao_task.c
new file mode 100644
index 00000000..f5850fa4
--- /dev/null
+++ b/src/core/ao_task.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+#define AO_NO_TASK_INDEX	0xff
+
+__xdata struct ao_task * __xdata ao_tasks[AO_NUM_TASKS];
+__data uint8_t ao_num_tasks;
+__data uint8_t ao_cur_task_index;
+__xdata struct ao_task *__data ao_cur_task;
+
+void
+ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *name) __reentrant
+{
+	uint8_t	__xdata *stack;
+	uint8_t task_id;
+	uint8_t t;
+	if (ao_num_tasks == AO_NUM_TASKS)
+		ao_panic(AO_PANIC_NO_TASK);
+	for (task_id = 1; task_id != 0; task_id++) {
+		for (t = 0; t < ao_num_tasks; t++)
+			if (ao_tasks[t]->task_id == task_id)
+				break;
+		if (t == ao_num_tasks)
+			break;
+	}
+	ao_tasks[ao_num_tasks++] = task;
+	task->task_id = task_id;
+	task->name = name;
+	/*
+	 * Construct a stack frame so that it will 'return'
+	 * to the start of the task
+	 */
+	stack = task->stack;
+
+	*stack++ = ((uint16_t) start);		/* 0 */
+	*stack++ = ((uint16_t) start) >> 8;	/* 1 */
+
+	/* and the stuff saved by ao_switch */
+	*stack++ = 0;				/* 2 acc */  
+	*stack++ = 0x80;			/* 3 IE */
+
+	/*  4 DPL
+	 *  5 DPH
+	 *  6 B
+	 *  7 R2
+	 *  8 R3
+	 *  9 R4
+	 * 10 R5
+	 * 11 R6
+	 * 12 R7
+	 * 13 R0
+	 * 14 R1
+	 * 15 PSW
+	 * 16 BP
+	 */
+	for (t = 0; t < 13; t++)
+		*stack++ = 0;
+
+	task->stack_count = 17;
+	task->wchan = NULL;
+}
+
+/* Task switching function. This must not use any stack variables */
+void
+ao_yield(void) __naked
+{
+
+	/* Save current context */
+	_asm
+		/* Push ACC first, as when restoring the context it must be restored
+		 * last (it is used to set the IE register). */
+		push	ACC
+		/* Store the IE register then enable interrupts. */
+		push	_IEN0
+		setb	_EA
+		push	DPL
+		push	DPH
+		push	b
+		push	ar2
+		push	ar3
+		push	ar4
+		push	ar5
+		push	ar6
+		push	ar7
+		push	ar0
+		push	ar1
+		push	PSW
+	_endasm;
+	PSW = 0;
+	_asm
+		push	_bp
+	_endasm;
+
+	if (ao_cur_task_index == AO_NO_TASK_INDEX)
+		ao_cur_task_index = ao_num_tasks-1;
+	else
+	{
+		uint8_t stack_len;
+		__data uint8_t *stack_ptr;
+		__xdata uint8_t *save_ptr;
+		/* Save the current stack */
+		stack_len = SP - (AO_STACK_START - 1);
+		ao_cur_task->stack_count = stack_len;
+		stack_ptr = (uint8_t __data *) AO_STACK_START;
+		save_ptr = (uint8_t __xdata *) ao_cur_task->stack;
+		do
+			*save_ptr++ = *stack_ptr++;
+		while (--stack_len);
+	}
+
+	/* Empty the stack; might as well let interrupts have the whole thing */
+	SP = AO_STACK_START - 1;
+
+	/* Find a task to run. If there isn't any runnable task,
+	 * this loop will run forever, which is just fine
+	 */
+	{
+		__pdata uint8_t	ao_next_task_index = ao_cur_task_index;
+		for (;;) {
+			++ao_next_task_index;
+			if (ao_next_task_index == ao_num_tasks)
+				ao_next_task_index = 0;
+
+			ao_cur_task = ao_tasks[ao_next_task_index];
+			if (ao_cur_task->wchan == NULL) {
+				ao_cur_task_index = ao_next_task_index;
+				break;
+			}
+
+			/* Check if the alarm is set for a time which has passed */
+			if (ao_cur_task->alarm &&
+			    (int16_t) (ao_time() - ao_cur_task->alarm) >= 0) {
+				ao_cur_task_index = ao_next_task_index;
+				break;
+			}
+
+			/* Enter lower power mode when there isn't anything to do */
+			if (ao_next_task_index == ao_cur_task_index)
+				PCON = PCON_IDLE;
+		}
+	}
+
+	{
+		uint8_t stack_len;
+		__data uint8_t *stack_ptr;
+		__xdata uint8_t *save_ptr;
+
+		/* Restore the old stack */
+		stack_len = ao_cur_task->stack_count;
+		SP = AO_STACK_START - 1 + stack_len;
+
+		stack_ptr = (uint8_t __data *) AO_STACK_START;
+		save_ptr = (uint8_t __xdata *) ao_cur_task->stack;
+		do
+			*stack_ptr++ = *save_ptr++;
+		while (--stack_len);
+	}
+
+	_asm
+		pop		_bp
+		pop		PSW
+		pop		ar1
+		pop		ar0
+		pop		ar7
+		pop		ar6
+		pop		ar5
+		pop		ar4
+		pop		ar3
+		pop		ar2
+		pop		b
+		pop		DPH
+		pop		DPL
+		/* The next byte of the stack is the IE register.  Only the global
+		enable bit forms part of the task context.  Pop off the IE then set
+		the global enable bit to match that of the stored IE register. */
+		pop		ACC
+		JB		ACC.7,0098$
+		CLR		_EA
+		LJMP	0099$
+	0098$:
+		SETB		_EA
+	0099$:
+		/* Finally pop off the ACC, which was the first register saved. */
+		pop		ACC
+		ret
+	_endasm;
+}
+
+uint8_t
+ao_sleep(__xdata void *wchan)
+{
+	__critical {
+		ao_cur_task->wchan = wchan;
+	}
+	ao_yield();
+	ao_cur_task->alarm = 0;
+	if (ao_cur_task->wchan) {
+		ao_cur_task->wchan = NULL;
+		return 1;
+	}
+	return 0;
+}
+
+void
+ao_wakeup(__xdata void *wchan)
+{
+	uint8_t	i;
+
+	for (i = 0; i < ao_num_tasks; i++)
+		if (ao_tasks[i]->wchan == wchan)
+			ao_tasks[i]->wchan = NULL;
+}
+
+void
+ao_alarm(uint16_t delay)
+{
+	/* Make sure we sleep *at least* delay ticks, which means adding
+	 * one to account for the fact that we may be close to the next tick
+	 */
+	if (!(ao_cur_task->alarm = ao_time() + delay + 1))
+		ao_cur_task->alarm = 1;
+}
+
+void
+ao_exit(void) __critical
+{
+	uint8_t	i;
+	ao_num_tasks--;
+	for (i = ao_cur_task_index; i < ao_num_tasks; i++)
+		ao_tasks[i] = ao_tasks[i+1];
+	ao_cur_task_index = AO_NO_TASK_INDEX;
+	ao_yield();
+	/* we'll never get back here */
+}
+
+void
+ao_task_info(void)
+{
+	uint8_t	i;
+	uint8_t pc_loc;
+	__xdata struct ao_task *task;
+
+	for (i = 0; i < ao_num_tasks; i++) {
+		task = ao_tasks[i];
+		pc_loc = task->stack_count - 17;
+		printf("%12s: wchan %04x pc %04x\n",
+		       task->name,
+		       (int16_t) task->wchan,
+		       (task->stack[pc_loc]) | (task->stack[pc_loc+1] << 8));
+	}
+}
+
+void
+ao_start_scheduler(void)
+{
+	ao_cur_task_index = AO_NO_TASK_INDEX;
+	ao_cur_task = NULL;
+	ao_yield();
+}