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