stack.c

/******************************************************************//**
 * @file 		stack.c
 * @brief 	This file is part of RT-Thread RTOS
 * 	COPYRIGHT (C) 2011, RT-Thread Development Team
 * @author 	Bernard, onelife
 * @version 	0.4 beta
 **********************************************************************
 * @section License
 * The license and distribution terms for this file may be found in the file LICENSE in this 
 * distribution or at http://www.rt-thread.org/license/LICENSE
 **********************************************************************
 * @section Change Logs
 * Date			Author		Notes
 * 2006-08-23 	Bernard 		first version
 * 2011-02-14	onelife		Modify for EFM32
 *********************************************************************/
 
/******************************************************************//**
* @addtogroup cortex-m3
* @{
*********************************************************************/

/* Includes -------------------------------------------------------------------*/
#include <rtthread.h>

/* Private typedef -------------------------------------------------------------*/
/* Private define --------------------------------------------------------------*/
/* Private macro --------------------------------------------------------------*/
/* Private variables ------------------------------------------------------------*/
/* Private function prototypes ---------------------------------------------------*/
/* Private functions ------------------------------------------------------------*/
/**
 * 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)
{
	unsigned long *stk;

	stk 	 = (unsigned long *)stack_addr;
	*(stk)   = 0x01000000L;					/* PSR */
	*(--stk) = (unsigned long)tentry;		/* entry point, pc */
	*(--stk) = (unsigned long)texit;		/* lr */
	*(--stk) = 0;							/* r12 */
	*(--stk) = 0;							/* r3 */
	*(--stk) = 0;							/* r2 */
	*(--stk) = 0;							/* r1 */
	*(--stk) = (unsigned long)parameter;	/* r0 : argument */

	*(--stk) = 0;							/* r11 */
	*(--stk) = 0;							/* r10 */
	*(--stk) = 0;							/* r9 */
	*(--stk) = 0;							/* r8 */
	*(--stk) = 0;							/* r7 */
	*(--stk) = 0;							/* r6 */
	*(--stk) = 0;							/* r5 */
	*(--stk) = 0;							/* r4 */

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

/******************************************************************//**
 * @}
*********************************************************************/