/*
**********************************************************************************************************
* INITIALIZE A TASK'S STACK
*
* Description: This function is called by OS_Task_Create() or OSTaskCreateExt() to initialize the stack
* frame of the task being created. This function is highly processor specific.
*
* Arguments : p_task Pointer to the task entry point address.
*
* p_arg Pointer to a user supplied data area that will be passed to the task
* when the task first executes.
*
* p_stk_base Pointer to the base address of the stack.
*
* stk_size Size of the stack, in number of CPU_STK elements.
*
* opt Options used to alter the behavior of OS_Task_StkInit().
* (see OS.H for OS_TASK_OPT_xxx).
*
* Returns : Always returns the location of the new top-of-stack' once the processor registers have
* been placed on the stack in the proper order.
*
* Note(s) : 1) Interrupts are enabled when task starts executing.
*
* 2) All tasks run in Thread mode, using process stack.
**********************************************************************************************************
*/
CPU_STK *OSTaskStkInit (OS_TASK_PTR p_task,
void *p_arg,
CPU_STK *p_stk_base,
CPU_STK *p_stk_limit,
CPU_STK_SIZE stk_size,
OS_OPT opt)
{
CPU_STK *p_stk;
(void)opt; /* Prevent compiler warning */
p_stk = &p_stk_base[stk_size]; /* Load stack pointer */
/* Registers stacked as if auto-saved on exception */
*--p_stk = (CPU_STK)0x01000000u; /* xPSR */
*--p_stk = (CPU_STK)p_task; /* Entry Point */
*--p_stk = (CPU_STK)OS_TaskReturn; /* R14 (LR) */
*--p_stk = (CPU_STK)0x12121212u; /* R12 */
*--p_stk = (CPU_STK)0x03030303u; /* R3 */
*--p_stk = (CPU_STK)0x02020202u; /* R2 */
*--p_stk = (CPU_STK)p_stk_limit; /* R1 */
*--p_stk = (CPU_STK)p_arg; /* R0 : argument */
/* Remaining registers saved on process stack */
*--p_stk = (CPU_STK)0x11111111u; /* R11 */
*--p_stk = (CPU_STK)0x10101010u; /* R10 */
*--p_stk = (CPU_STK)0x09090909u; /* R9 */
*--p_stk = (CPU_STK)0x08080808u; /* R8 */
*--p_stk = (CPU_STK)0x07070707u; /* R7 */
*--p_stk = (CPU_STK)0x06060606u; /* R6 */
*--p_stk = (CPU_STK)0x05050505u; /* R5 */
*--p_stk = (CPU_STK)0x04040404u; /* R4 */
return (p_stk);
}
请问几个寄存器的地址是怎么来的，谢谢。 |
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