stack.c

/*
 * File      : stack.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006, RT-Thread Development Team
 *
 *  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 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.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2011-01-13     weety
 */
#include <rtthread.h>

/*****************************/
/* CPU Mode                  */
/*****************************/
#define USERMODE		0x10
#define FIQMODE			0x11
#define IRQMODE			0x12
#define SVCMODE			0x13
#define ABORTMODE		0x17
#define UNDEFMODE		0x1b
#define MODEMASK		0x1f
#define NOINT			0xc0

/**
 * This function will initialize thread stack
 *
 * @param tentry the entry of thread
 * @param parameter the parameter of entry 
 * @param stack_addr the beginning stack address
 * @param texit the function will be called when thread exit
 *
 * @return stack address
 */
rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
	rt_uint8_t *stack_addr, void *texit)
{
	rt_uint32_t *stk;

	stk 	 = (rt_uint32_t*)stack_addr;
	*(stk) 	 = (rt_uint32_t)tentry;			/* entry point */
	*(--stk) = (rt_uint32_t)texit;			/* lr */
	*(--stk) = 0;							/* r12 */
	*(--stk) = 0;							/* r11 */
	*(--stk) = 0;							/* r10 */
	*(--stk) = 0;							/* r9 */
	*(--stk) = 0;							/* r8 */
	*(--stk) = 0;							/* r7 */
	*(--stk) = 0;							/* r6 */
	*(--stk) = 0;							/* r5 */
	*(--stk) = 0;							/* r4 */
	*(--stk) = 0;							/* r3 */
	*(--stk) = 0;							/* r2 */
	*(--stk) = 0;							/* r1 */
	*(--stk) = (rt_uint32_t)parameter;		/* r0 : argument */

	/* cpsr */
	if ((rt_uint32_t)tentry & 0x01)
		*(--stk) = SVCMODE | 0x20;			/* thumb mode */
	else
		*(--stk) = SVCMODE;					/* arm mode   */

	/* return task's current stack address */
	return (rt_uint8_t *)stk;
}