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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_thread.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_system_preempt_check PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function checks for preemption that could have occurred as a */
/* result scheduling activities occurring while the preempt disable */
/* flag was set. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _tx_thread_system_return Return to the system */
/* */
/* CALLED BY */
/* */
/* Other ThreadX Components */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 Yuxin Zhou Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
VOID _tx_thread_system_preempt_check(VOID)
{
ULONG combined_flags;
TX_THREAD *current_thread;
TX_THREAD *thread_ptr;
/* Combine the system state and preempt disable flags into one for comparison. */
TX_THREAD_SYSTEM_RETURN_CHECK(combined_flags)
/* Determine if we are in a system state (ISR or Initialization) or internal preemption is disabled. */
if (combined_flags == ((ULONG) 0))
{
/* No, at thread execution level so continue checking for preemption. */
/* Pickup thread pointer. */
TX_THREAD_GET_CURRENT(current_thread)
/* Pickup the next execute pointer. */
thread_ptr = _tx_thread_execute_ptr;
/* Determine if preemption should take place. */
if (current_thread != thread_ptr)
{
#ifdef TX_ENABLE_STACK_CHECKING
/* Check this thread's stack. */
TX_THREAD_STACK_CHECK(thread_ptr)
#endif
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Determine if an idle system return is present. */
if (thread_ptr == TX_NULL)
{
/* Yes, increment the return to idle return count. */
_tx_thread_performance_idle_return_count++;
}
else
{
/* No, there is another thread ready to run and will be scheduled upon return. */
_tx_thread_performance_non_idle_return_count++;
}
#endif
/* Return to the system so the higher priority thread can be scheduled. */
_tx_thread_system_return();
}
}
}