osKernelAddThreads.c

void OsInitThreadStack()
{
	/// Enter critical section
	/// Disable interrupts
	__asm("CPSID   I");
	/// Make the TCB linked list circular
	tcbs[0].nextPt = &tcbs[1];
	tcbs[1].nextPt = &tcbs[0];

	/// Setup stack for task0

	/// Setup the stack such that it is holding one task context.
	/// Remember it is a descending stack and a context consists of 16 registers.
	tcbs[0].stackPt = &TCB_STACK[0][STACKSIZE-16];
	/// Set the 'T' bit in stacked xPSR to '1' to notify processor
	/// on exception return about the thumb state. V6-m and V7-m cores
	/// can only support thumb state hence this should be always set
	/// to '1'.
	TCB_STACK[0][STACKSIZE-1] = 0x01000000;
	/// Set the stacked PC to point to the task
	TCB_STACK[0][STACKSIZE-2] = (int32_t)(Task0);


	/// Setup stack for task1

	/// Setup the stack such that it is holding one task context.
	/// Remember it is a descending stack and a context consists of 16 registers.
    tcbs[1].stackPt = &TCB_STACK[1][STACKSIZE-16];
    /// Set the 'T' bit in stacked xPSR to '1' to notify processor
    /// on exception return about the thumb state. V6-m and V7-m cores
    /// can only support thumb state hence this should be always set
    /// to '1'.
    TCB_STACK[1][STACKSIZE-1] = 0x01000000;
    /// Set the stacked PC to point to the task
    TCB_STACK[1][STACKSIZE-2] = (int32_t)(Task1);
    /// Make current tcb pointer point to task0
    pCurntTcb = &tcbs[0];
    /// Enable interrupts
    __asm("CPSIE   I ");
}