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/***************************************************************************
* Copyright (C) 2026 Eclipse ThreadX contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* AI Disclosure: This file was largely AI-generated by Codex (gpt 5.4).
* The AI-generated portions may be considered public domain (CC0-1.0)
* and not subject to the project's licence. The human contributor has
* reviewed and verified that the code is correct.
*
* SPDX-License-Identifier: MIT and CC0-1.0
**************************************************************************/
// Some portions generated by Codex (gpt 5.4).
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_thread.h"
#include "tx_timer.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_context_restore Win64/MSVC */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function restores the interrupt context if it is processing a */
/* nested interrupt. If not, it returns to the interrupt thread if no */
/* preemption is necessary. Otherwise, if preemption is necessary or */
/* if no thread was running, the function returns to the scheduler. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* ReleaseSemaphore Win32 release semaphore */
/* ResumeThread Win32 resume thread */
/* _tx_win32_critical_section_obtain Obtain critical section */
/* _tx_win32_critical_section_release Release critical section */
/* */
/* CALLED BY */
/* */
/* ISRs Interrupt Service Routines */
/* */
/**************************************************************************/
VOID _tx_thread_context_restore(VOID)
{
TX_THREAD *execute_thread;
/* Enter critical section to ensure other threads are not playing with
the core ThreadX data structures. */
_tx_win32_critical_section_obtain(&_tx_win32_critical_section);
/* Debug entry. */
_tx_win32_debug_entry_insert("CONTEXT_RESTORE", __FILE__, __LINE__);
/* Decrement the nested interrupt count. */
_tx_thread_system_state--;
/* Pickup the execute thread pointer. */
execute_thread = _tx_thread_execute_ptr;
/* Determine if this is the first nested interrupt and if a ThreadX
application thread was running at the time. */
if ((!_tx_thread_system_state) && (_tx_thread_current_ptr))
{
/* Yes, this is the first and last interrupt processed. */
/* Check to see if preemption is required. */
if ((_tx_thread_preempt_disable == 0) && (_tx_thread_current_ptr != _tx_thread_execute_ptr))
{
/* Preempt the running application thread. We don't need to suspend the
application thread since that is done in the context save processing. */
/* Indicate that this thread was suspended asynchronously. */
_tx_thread_current_ptr -> tx_thread_win32_suspension_type = 1;
/* Save the remaining time-slice and disable it. */
if (_tx_timer_time_slice)
{
_tx_thread_current_ptr -> tx_thread_time_slice = _tx_timer_time_slice;
_tx_timer_time_slice = 0;
}
/* Clear the current thread pointer. */
_tx_thread_current_ptr = TX_NULL;
/* Block the timer ISR until the resumed thread has observed the wakeup. */
_tx_win32_timer_waiting = TX_TRUE;
/* Wakeup the system thread by setting the system semaphore. */
ReleaseSemaphore(_tx_win32_scheduler_semaphore, 1, NULL);
_tx_win32_scheduler_wake();
/* If the timer made a solicited wakeup ready, let that thread run before
the host timer ISR continues. */
if ((execute_thread != TX_NULL) &&
(execute_thread -> tx_thread_win32_suspension_type == 0))
{
/* Release the critical section while the scheduler runs. */
_tx_win32_critical_section_release_all(&_tx_win32_critical_section);
WaitForSingleObject(_tx_win32_isr_semaphore, INFINITE);
_tx_win32_critical_section_obtain(&_tx_win32_critical_section);
while (WaitForSingleObject(_tx_win32_isr_semaphore, 0) == WAIT_OBJECT_0)
{
}
}
/* The timer ISR no longer needs to hold off future ticks. */
_tx_win32_timer_waiting = TX_FALSE;
}
else
{
/* Since preemption is not required, resume the interrupted thread. */
ResumeThread(_tx_thread_current_ptr -> tx_thread_win32_thread_handle);
}
}
else if ((!_tx_thread_system_state) && (execute_thread != TX_NULL))
{
/* The timer made a thread ready while the scheduler was idle. Keep the
timer ISR blocked until the solicited wakeup has started running. */
_tx_win32_timer_waiting = TX_TRUE;
_tx_win32_scheduler_wake();
if (execute_thread -> tx_thread_win32_suspension_type == 0)
{
/* Release the critical section while the scheduler runs. */
_tx_win32_critical_section_release_all(&_tx_win32_critical_section);
WaitForSingleObject(_tx_win32_isr_semaphore, INFINITE);
_tx_win32_critical_section_obtain(&_tx_win32_critical_section);
while (WaitForSingleObject(_tx_win32_isr_semaphore, 0) == WAIT_OBJECT_0)
{
}
}
_tx_win32_timer_waiting = TX_FALSE;
}
/* Leave Win32 critical section. */
_tx_win32_critical_section_release_all(&_tx_win32_critical_section);
}
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