298 lines
12 KiB
C
298 lines
12 KiB
C
/***************************************************************************
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* Copyright (c) 2024 Microsoft Corporation
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*
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* This program and the accompanying materials are made available under the
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* terms of the MIT License which is available at
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* https://opensource.org/licenses/MIT.
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*
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* SPDX-License-Identifier: MIT
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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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#define TX_THREAD_SMP_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_initialize.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 SMP */
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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_smp_rebalance_execute_list Rebalance the execution list */
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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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/* 09-30-2020 William E. Lamie Initial 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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UINT core_index;
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#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
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ULONG priority_bit;
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UINT base_priority;
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UINT priority_bit_set;
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ULONG priority_map;
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UINT next_preempted;
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TX_THREAD *preempted_thread;
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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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#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 (new_threshold < thread_ptr -> tx_thread_user_priority)
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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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/* Default status to success. */
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status = TX_SUCCESS;
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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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/* Restore interrupts. */
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TX_RESTORE
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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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/* 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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/* Determine if the thread is ready and scheduled. */
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if (thread_ptr -> tx_thread_state == TX_READY)
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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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/* Yes, preemption-threshold is being disabled. */
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/* Determine if this thread was scheduled with preemption-threshold in force. */
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if (_tx_thread_preemption_threshold_list[thread_ptr -> tx_thread_priority] == thread_ptr)
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{
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/* Clear the entry in the preempted list. */
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_tx_thread_preemption_threshold_list[thread_ptr -> tx_thread_priority] = TX_NULL;
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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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/* Determine if this thread has global preemption disabled. */
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if (thread_ptr == _tx_thread_preemption__threshold_scheduled)
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{
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/* Clear the global preemption disable flag. */
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_tx_thread_preemption__threshold_scheduled = TX_NULL;
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#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
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/* Calculate the first thread with preemption-threshold active. */
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#if TX_MAX_PRIORITIES > 32
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if (_tx_thread_preempted_map_active != ((ULONG) 0))
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#else
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if (_tx_thread_preempted_maps[0] != ((ULONG) 0))
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#endif
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{
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#if TX_MAX_PRIORITIES > 32
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/* Calculate the index to find the next highest priority thread ready for execution. */
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priority_map = _tx_thread_preempted_map_active;
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/* Calculate the lowest bit set in the priority map. */
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TX_LOWEST_SET_BIT_CALCULATE(priority_map, map_index)
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/* Calculate the base priority as well. */
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base_priority = map_index * ((UINT) 32);
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#else
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/* Setup the base priority to zero. */
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base_priority = ((UINT) 0);
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#endif
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/* Setup temporary preempted map. */
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priority_map = _tx_thread_preempted_maps[MAP_INDEX];
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/* Calculate the lowest bit set in the priority map. */
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TX_LOWEST_SET_BIT_CALCULATE(priority_map, priority_bit_set)
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/* Move priority bit set into priority bit. */
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priority_bit = (ULONG) priority_bit_set;
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/* Setup the highest priority preempted thread. */
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next_preempted = base_priority + priority_bit;
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/* Pickup the previously preempted thread. */
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preempted_thread = _tx_thread_preemption_threshold_list[next_preempted];
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/* Pickup the preempted thread. */
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_tx_thread_preemption__threshold_scheduled = preempted_thread;
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}
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#endif
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}
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/* See if preemption needs to take place. */
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#ifdef TX_THREAD_SMP_DEBUG_ENABLE
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/* Debug entry. */
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_tx_thread_smp_debug_entry_insert(12, 0, thread_ptr);
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#endif
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/* Pickup the index. */
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core_index = TX_SMP_CORE_ID;
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/* Call the rebalance routine. This routine maps cores and ready threads. */
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_tx_thread_smp_rebalance_execute_list(core_index);
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#ifdef TX_THREAD_SMP_DEBUG_ENABLE
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/* Debug entry. */
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_tx_thread_smp_debug_entry_insert(13, 0, thread_ptr);
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#endif
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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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}
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else
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{
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/* Restore interrupts. */
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TX_RESTORE
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}
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}
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/* Return completion status. */
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return(status);
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}
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