/* * File : stack.c * This file is part of RT-Thread RTOS * COPYRIGHT (C) 2011, 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://www.rt-thread.org/license/LICENSE * * Change Logs: * Date Author Notes * 2011-09-23 Bernard the first version * 2011-10-05 Bernard add thumb mode */ #include <rtthread.h> #include "am33xx.h" /** * @addtogroup AM33xx */ /*@{*/ /** * 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; } /*@}*/