rt-thread-official/libcpu/ia32/stack.c

/*
 * File      : stack.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006, RT-Thread Development Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://openlab.rt-thread.com/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 */
 
#include <rtthread.h>

#include <i386.h>

/**
 * @addtogroup I386
 */
/*@{*/

/**
 * 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) = (unsigned long)parameter;
	*(--stk) = (unsigned long)texit;
	*(--stk) = 0x200;						/*flags*/
	*(--stk) = 0x08;						/*cs*/
	*(--stk) = (unsigned long)tentry;		/*eip*/
	*(--stk) = 0;							/*irqno*/
	*(--stk) = 0x10;						/*ds*/
	*(--stk) = 0x10;						/*es*/
	*(--stk) = 0;							/*eax*/
	*(--stk) = 0;							/*ecx*/
	*(--stk) = 0;							/*edx*/
	*(--stk) = 0;							/*ebx*/
	*(--stk) = 0;							/*esp*/
	*(--stk) = 0;							/*ebp*/
	*(--stk) = 0;							/*esi*/
	*(--stk) = 0;							/*edi*/

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