283 lines
13 KiB
C
283 lines
13 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_trace.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_preemption_change 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 processes preemption-threshold change requests. The */
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/* previous preemption is returned to the caller. If the new request */
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/* allows a higher priority thread to execute, preemption takes place */
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/* inside of this function. */
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/* */
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/* INPUT */
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/* */
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/* thread_ptr Pointer to thread */
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/* new_threshold New preemption threshold */
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/* old_threshold Old preemption threshold */
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/* */
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/* OUTPUT */
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/* */
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/* status Service return status */
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/* */
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/* CALLS */
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/* */
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/* _tx_thread_system_preempt_check Check for preemption */
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/* */
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/* CALLED BY */
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/* */
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/* Application Code */
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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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UINT _tx_thread_preemption_change(TX_THREAD *thread_ptr, UINT new_threshold, UINT *old_threshold)
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{
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TX_INTERRUPT_SAVE_AREA
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#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
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ULONG priority_bit;
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#if TX_MAX_PRIORITIES > 32
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UINT map_index;
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#endif
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#endif
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UINT status;
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/* Default status to success. */
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status = TX_SUCCESS;
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#ifdef TX_DISABLE_PREEMPTION_THRESHOLD
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/* Only allow 0 (disable all preemption) and returning preemption-threshold to the
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current thread priority if preemption-threshold is disabled. All other threshold
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values are converted to 0. */
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if (thread_ptr -> tx_thread_user_priority != new_threshold)
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{
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/* Is the new threshold zero? */
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if (new_threshold != ((UINT) 0))
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{
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/* Convert the new threshold to disable all preemption, since preemption-threshold is
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not supported. */
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new_threshold = ((UINT) 0);
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}
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}
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#endif
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/* Lockout interrupts while the thread is being resumed. */
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TX_DISABLE
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/* If trace is enabled, insert this event into the trace buffer. */
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TX_TRACE_IN_LINE_INSERT(TX_TRACE_THREAD_PREEMPTION_CHANGE, thread_ptr, new_threshold, thread_ptr -> tx_thread_preempt_threshold, thread_ptr -> tx_thread_state, TX_TRACE_THREAD_EVENTS)
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/* Log this kernel call. */
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TX_EL_THREAD_PREEMPTION_CHANGE_INSERT
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/* Determine if the new threshold is greater than the current user priority. */
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if (new_threshold > thread_ptr -> tx_thread_user_priority)
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{
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/* Return error. */
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status = TX_THRESH_ERROR;
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}
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else
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{
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#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
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/* Determine if the new threshold is the same as the priority. */
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if (thread_ptr -> tx_thread_user_priority == new_threshold)
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{
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/* Determine if this thread is at the head of the list. */
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if (_tx_thread_priority_list[thread_ptr -> tx_thread_priority] == thread_ptr)
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{
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#if TX_MAX_PRIORITIES > 32
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/* Calculate the index into the bit map array. */
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map_index = (thread_ptr -> tx_thread_priority)/((UINT) 32);
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#endif
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/* Yes, this thread is at the front of the list. Make sure
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the preempted bit is cleared for this thread. */
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TX_MOD32_BIT_SET(thread_ptr -> tx_thread_priority, priority_bit)
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_tx_thread_preempted_maps[MAP_INDEX] = _tx_thread_preempted_maps[MAP_INDEX] & (~(priority_bit));
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#if TX_MAX_PRIORITIES > 32
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/* Determine if there are any other bits set in this preempt map. */
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if (_tx_thread_preempted_maps[MAP_INDEX] == ((ULONG) 0))
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{
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/* No, clear the active bit to signify this preempt map has nothing set. */
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TX_DIV32_BIT_SET(thread_ptr -> tx_thread_priority, priority_bit)
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_tx_thread_preempted_map_active = _tx_thread_preempted_map_active & (~(priority_bit));
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}
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#endif
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}
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}
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#endif
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/* Return the user's preemption-threshold. */
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*old_threshold = thread_ptr -> tx_thread_user_preempt_threshold;
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/* Setup the new threshold. */
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thread_ptr -> tx_thread_user_preempt_threshold = new_threshold;
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/* Determine if the new threshold represents a higher priority than the priority inheritance threshold. */
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if (new_threshold < thread_ptr -> tx_thread_inherit_priority)
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{
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/* Update the actual preemption-threshold with the new threshold. */
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thread_ptr -> tx_thread_preempt_threshold = new_threshold;
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}
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else
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{
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/* Update the actual preemption-threshold with the priority inheritance. */
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thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
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}
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/* Is the thread priority less than the current highest priority? If not, no preemption is required. */
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if (_tx_thread_highest_priority < thread_ptr -> tx_thread_priority)
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{
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/* Is the new thread preemption-threshold less than the current highest priority? If not, no preemption is required. */
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if (_tx_thread_highest_priority < new_threshold)
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{
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/* If the current execute pointer is the same at this thread, preemption needs to take place. */
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if (_tx_thread_execute_ptr == thread_ptr)
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{
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/* Preemption needs to take place. */
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#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
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/* Determine if this thread has preemption threshold set. */
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if (thread_ptr -> tx_thread_preempt_threshold != thread_ptr -> tx_thread_priority)
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{
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#if TX_MAX_PRIORITIES > 32
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/* Calculate the index into the bit map array. */
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map_index = (thread_ptr -> tx_thread_priority)/((UINT) 32);
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/* Set the active bit to remember that the preempt map has something set. */
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TX_DIV32_BIT_SET(thread_ptr -> tx_thread_priority, priority_bit)
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_tx_thread_preempted_map_active = _tx_thread_preempted_map_active | priority_bit;
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#endif
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/* Remember that this thread was preempted by a thread above the thread's threshold. */
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TX_MOD32_BIT_SET(thread_ptr -> tx_thread_priority, priority_bit)
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_tx_thread_preempted_maps[MAP_INDEX] = _tx_thread_preempted_maps[MAP_INDEX] | priority_bit;
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}
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#endif
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#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
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/* Determine if the caller is an interrupt or from a thread. */
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if (TX_THREAD_GET_SYSTEM_STATE() == ((ULONG) 0))
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{
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/* Caller is a thread, so this is a solicited preemption. */
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_tx_thread_performance_solicited_preemption_count++;
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/* Increment the thread's solicited preemption counter. */
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thread_ptr -> tx_thread_performance_solicited_preemption_count++;
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}
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/* Remember the thread that preempted this thread. */
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thread_ptr -> tx_thread_performance_last_preempting_thread = _tx_thread_priority_list[_tx_thread_highest_priority];
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/* Is the execute pointer different? */
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if (_tx_thread_performance_execute_log[_tx_thread_performance__execute_log_index] != _tx_thread_execute_ptr)
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{
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/* Move to next entry. */
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_tx_thread_performance__execute_log_index++;
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/* Check for wrap condition. */
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if (_tx_thread_performance__execute_log_index >= TX_THREAD_EXECUTE_LOG_SIZE)
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{
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/* Set the index to the beginning. */
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_tx_thread_performance__execute_log_index = ((UINT) 0);
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}
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/* Log the new execute pointer. */
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_tx_thread_performance_execute_log[_tx_thread_performance__execute_log_index] = _tx_thread_execute_ptr;
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}
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#endif
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/* Setup the highest priority thread to execute. */
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_tx_thread_execute_ptr = _tx_thread_priority_list[_tx_thread_highest_priority];
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/* Restore interrupts. */
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TX_RESTORE
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/* Check for preemption. */
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_tx_thread_system_preempt_check();
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/* Disable interrupts. */
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TX_DISABLE
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}
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}
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}
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}
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/* Restore interrupts. */
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TX_RESTORE
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/* Return completion status. */
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return(status);
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}
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