rt-thread/libcpu/arm/arm926/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      copy from mini2440
 */
#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 */
    *(--stk) = SVCMODE;                        /* cpsr */
    *(--stk) = SVCMODE;                        /* spsr */

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