ostaskosinit.txt

20080718μC_OS－Ⅱ实时嵌入式操作系统源代码

void *OSTaskStkInit (void (*task)(void *pd), void *pdata, void *ptos, INT16U opt)
{
    INT16U *stk;


    opt    = opt;                           /* 'opt' is not used, prevent warning                      */
    stk    = (INT16U *)ptos;                /* Load stack pointer                                      */
    *stk-- = (INT16U)FP_SEG(pdata);         /* Simulate call to function with argument                 */
    *stk-- = (INT16U)FP_OFF(pdata);         
    *stk-- = (INT16U)FP_SEG(task);
    *stk-- = (INT16U)FP_OFF(task);
    *stk-- = (INT16U)0x0202;                /* SW = Interrupts enabled                                 */
    *stk-- = (INT16U)FP_SEG(task);          /* Put pointer to task   on top of stack                   */
    *stk-- = (INT16U)FP_OFF(task);
    *stk-- = (INT16U)0xAAAA;                /* AX = 0xAAAA                                             */
    *stk-- = (INT16U)0xCCCC;                /* CX = 0xCCCC                                             */
    *stk-- = (INT16U)0xDDDD;                /* DX = 0xDDDD                                             */
    *stk-- = (INT16U)0xBBBB;                /* BX = 0xBBBB                                             */
    *stk-- = (INT16U)0x0000;                /* SP = 0x0000                                             */
    *stk-- = (INT16U)0x1111;                /* BP = 0x1111                                             */
    *stk-- = (INT16U)0x2222;                /* SI = 0x2222                                             */
    *stk-- = (INT16U)0x3333;                /* DI = 0x3333                                             */
    *stk-- = (INT16U)0x4444;                /* ES = 0x4444                                             */
    *stk   = _DS;                           /* DS = Current value of DS                                */
    return ((void *)stk);
}