求助 0x01000000L; /* PSR */是什么意思

ksssss · 发表于 2019-2-6 23:37:57

[mw_shl_code=applescript,true]/*  初始化线程栈  */
rt_uint8_t *rt_hw_stack_init(void    *tentry,
                                 void    *parameter,
                                                                                                               rt_uint8_t *stack_addr)
{
   struct stack_frame *stack_frame;
         rt_uint8_t  *stk;
         unsigned long  i;

         /* 获取栈顶指针 rt_hw_stack_init 在调用时，传给stack_addr的是（栈顶指针-4）*/
         stk = stack_addr + sizeof(rt_uint32_t);

         /*让stk指针向下8字节对齐*/
         stk = (rt_uint8_t *)RT_ALIGN_DOWN((rt_uint32_t)stk,8);

         /*stk指针继续向下移动sizeof(struct stack_frame)个偏移*/
         stk -=sizeof(struct stack_frame);

         /* 将stk指针强制转换为 stack_frame类型后存到stack_frame*/
         stack_frame =(struct stack_frame *)stk;

         /*以stack_frame 为起始地址，将栈空间里面的sizeof(struct stack_frame)个内存初始化为0xdeadbeef */
         for(i=0; i<sizeof(struct stack_frame)/sizeof(rt_uint32_t); i++)
         {
                  ((rt_uint32_t *)stack_frame) = 0xdeadbeef;
               }

                     /*初始化异常发生时自动保存的寄存器*/
                     stack_frame->exception_stack_frame.r0 =(unsigned long)parameter;
                     stack_frame->exception_stack_frame.r1  = 0;                      /* r1 */
   stack_frame->exception_stack_frame.r2  = 0;                      /* r2 */
   stack_frame->exception_stack_frame.r3  = 0;                      /* r3 */
   stack_frame->exception_stack_frame.r12 = 0;                      /* r12 */
   stack_frame->exception_stack_frame.lr  = 0;                      /* lr */
   stack_frame->exception_stack_frame.pc  = (unsigned long)tentry; /* entry point, pc */
   stack_frame->exception_stack_frame.psr = 0x01000000L;             /* PSR */

                     /* 返回线程指针 */
                     return stk;
}
[/mw_shl_code]