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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 */
/** */
/** Event Flags */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_trace.h"
#include "tx_thread.h"
#include "tx_event_flags.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_event_flags_get PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function gets the specified event flags from the group, */
/* according to the get option. The get option also specifies whether */
/* or not the retrieved flags are cleared. */
/* */
/* INPUT */
/* */
/* group_ptr Pointer to group control block */
/* requested_event_flags Event flags requested */
/* get_option Specifies and/or and clear options*/
/* actual_flags_ptr Pointer to place the actual flags */
/* the service retrieved */
/* wait_option Suspension option */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _tx_thread_system_suspend Suspend thread service */
/* _tx_thread_system_ni_suspend Non-interruptable suspend thread */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* 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 */
/* */
/**************************************************************************/
UINT _tx_event_flags_get(TX_EVENT_FLAGS_GROUP *group_ptr, ULONG requested_flags,
UINT get_option, ULONG *actual_flags_ptr, ULONG wait_option)
{
TX_INTERRUPT_SAVE_AREA
UINT status;
UINT and_request;
UINT clear_request;
ULONG current_flags;
ULONG flags_satisfied;
#ifndef TX_NOT_INTERRUPTABLE
ULONG delayed_clear_flags;
#endif
UINT suspended_count;
TX_THREAD *thread_ptr;
TX_THREAD *next_thread;
TX_THREAD *previous_thread;
#ifndef TX_NOT_INTERRUPTABLE
UINT interrupted_set_request;
#endif
/* Disable interrupts to examine the event flags group. */
TX_DISABLE
#ifdef TX_EVENT_FLAGS_ENABLE_PERFORMANCE_INFO
/* Increment the total event flags get counter. */
_tx_event_flags_performance_get_count++;
/* Increment the number of event flags gets on this semaphore. */
group_ptr -> tx_event_flags_group__performance_get_count++;
#endif
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_EVENT_FLAGS_GET, group_ptr, requested_flags, group_ptr -> tx_event_flags_group_current, get_option, TX_TRACE_EVENT_FLAGS_EVENTS)
/* Log this kernel call. */
TX_EL_EVENT_FLAGS_GET_INSERT
/* Pickup current flags. */
current_flags = group_ptr -> tx_event_flags_group_current;
/* Apply the event flag option mask. */
and_request = (get_option & TX_AND);
#ifdef TX_NOT_INTERRUPTABLE
/* Check for AND condition. All flags must be present to satisfy request. */
if (and_request == TX_AND)
{
/* AND request is present. */
/* Calculate the flags present. */
flags_satisfied = (current_flags & requested_flags);
/* Determine if they satisfy the AND request. */
if (flags_satisfied != requested_flags)
{
/* No, not all the requested flags are present. Clear the flags present variable. */
flags_satisfied = ((ULONG) 0);
}
}
else
{
/* OR request is present. Simply or the requested flags and the current flags. */
flags_satisfied = (current_flags & requested_flags);
}
/* Determine if the request is satisfied. */
if (flags_satisfied != ((ULONG) 0))
{
/* Return the actual event flags that satisfied the request. */
*actual_flags_ptr = current_flags;
/* Pickup the clear bit. */
clear_request = (get_option & TX_EVENT_FLAGS_CLEAR_MASK);
/* Determine whether or not clearing needs to take place. */
if (clear_request == TX_TRUE)
{
/* Yes, clear the flags that satisfied this request. */
group_ptr -> tx_event_flags_group_current =
group_ptr -> tx_event_flags_group_current & (~requested_flags);
}
/* Return success. */
status = TX_SUCCESS;
}
#else
/* Pickup delayed clear flags. */
delayed_clear_flags = group_ptr -> tx_event_flags_group_delayed_clear;
/* Determine if there are any delayed clear operations pending. */
if (delayed_clear_flags != ((ULONG) 0))
{
/* Yes, apply them to the current flags. */
current_flags = current_flags & (~delayed_clear_flags);
}
/* Check for AND condition. All flags must be present to satisfy request. */
if (and_request == TX_AND)
{
/* AND request is present. */
/* Calculate the flags present. */
flags_satisfied = (current_flags & requested_flags);
/* Determine if they satisfy the AND request. */
if (flags_satisfied != requested_flags)
{
/* No, not all the requested flags are present. Clear the flags present variable. */
flags_satisfied = ((ULONG) 0);
}
}
else
{
/* OR request is present. Simply AND together the requested flags and the current flags
to see if any are present. */
flags_satisfied = (current_flags & requested_flags);
}
/* Determine if the request is satisfied. */
if (flags_satisfied != ((ULONG) 0))
{
/* Yes, this request can be handled immediately. */
/* Return the actual event flags that satisfied the request. */
*actual_flags_ptr = current_flags;
/* Pickup the clear bit. */
clear_request = (get_option & TX_EVENT_FLAGS_CLEAR_MASK);
/* Determine whether or not clearing needs to take place. */
if (clear_request == TX_TRUE)
{
/* Set interrupted set request flag to false. */
interrupted_set_request = TX_FALSE;
/* Determine if the suspension list is being processed by an interrupted
set request. */
if (group_ptr -> tx_event_flags_group_suspended_count != TX_NO_SUSPENSIONS)
{
if (group_ptr -> tx_event_flags_group_suspension_list == TX_NULL)
{
/* Set the interrupted set request flag. */
interrupted_set_request = TX_TRUE;
}
}
/* Was a set request interrupted? */
if (interrupted_set_request == TX_TRUE)
{
/* A previous set operation is was interrupted, we need to defer the
event clearing until the set operation is complete. */
/* Remember the events to clear. */
group_ptr -> tx_event_flags_group_delayed_clear =
group_ptr -> tx_event_flags_group_delayed_clear | requested_flags;
}
else
{
/* Yes, clear the flags that satisfied this request. */
group_ptr -> tx_event_flags_group_current =
group_ptr -> tx_event_flags_group_current & ~requested_flags;
}
}
/* Set status to success. */
status = TX_SUCCESS;
}
#endif
else
{
/* Determine if the request specifies suspension. */
if (wait_option != TX_NO_WAIT)
{
/* Determine if the preempt disable flag is non-zero. */
if (_tx_thread_preempt_disable != ((UINT) 0))
{
/* Suspension is not allowed if the preempt disable flag is non-zero at this point, return error completion. */
status = TX_NO_EVENTS;
}
else
{
/* Prepare for suspension of this thread. */
#ifdef TX_EVENT_FLAGS_ENABLE_PERFORMANCE_INFO
/* Increment the total event flags suspensions counter. */
_tx_event_flags_performance_suspension_count++;
/* Increment the number of event flags suspensions on this semaphore. */
group_ptr -> tx_event_flags_group___performance_suspension_count++;
#endif
/* Pickup thread pointer. */
TX_THREAD_GET_CURRENT(thread_ptr)
/* Setup cleanup routine pointer. */
thread_ptr -> tx_thread_suspend_cleanup = &(_tx_event_flags_cleanup);
/* Remember which event flags we are looking for. */
thread_ptr -> tx_thread_suspend_info = requested_flags;
/* Save the get option as well. */
thread_ptr -> tx_thread_suspend_option = get_option;
/* Save the destination for the current events. */
thread_ptr -> tx_thread_additional_suspend_info = (VOID *) actual_flags_ptr;
/* Setup cleanup information, i.e. this event flags group control
block. */
thread_ptr -> tx_thread_suspend_control_block = (VOID *) group_ptr;
#ifndef TX_NOT_INTERRUPTABLE
/* Increment the suspension sequence number, which is used to identify
this suspension event. */
thread_ptr -> tx_thread_suspension_sequence++;
#endif
/* Pickup the suspended count. */
suspended_count = group_ptr -> tx_event_flags_group_suspended_count;
/* Setup suspension list. */
if (suspended_count == TX_NO_SUSPENSIONS)
{
/* No other threads are suspended. Setup the head pointer and
just setup this threads pointers to itself. */
group_ptr -> tx_event_flags_group_suspension_list = thread_ptr;
thread_ptr -> tx_thread_suspended_next = thread_ptr;
thread_ptr -> tx_thread_suspended_previous = thread_ptr;
}
else
{
/* This list is not NULL, add current thread to the end. */
next_thread = group_ptr -> tx_event_flags_group_suspension_list;
thread_ptr -> tx_thread_suspended_next = next_thread;
previous_thread = next_thread -> tx_thread_suspended_previous;
thread_ptr -> tx_thread_suspended_previous = previous_thread;
previous_thread -> tx_thread_suspended_next = thread_ptr;
next_thread -> tx_thread_suspended_previous = thread_ptr;
}
/* Increment the number of threads suspended. */
group_ptr -> tx_event_flags_group_suspended_count++;
/* Set the state to suspended. */
thread_ptr -> tx_thread_state = TX_EVENT_FLAG;
#ifdef TX_NOT_INTERRUPTABLE
/* Call actual non-interruptable thread suspension routine. */
_tx_thread_system_ni_suspend(thread_ptr, wait_option);
/* Return the completion status. */
status = thread_ptr -> tx_thread_suspend_status;
#else
/* Set the suspending flag. */
thread_ptr -> tx_thread_suspending = TX_TRUE;
/* Setup the timeout period. */
thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = wait_option;
/* Temporarily disable preemption. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
/* Call actual thread suspension routine. */
_tx_thread_system_suspend(thread_ptr);
/* Disable interrupts. */
TX_DISABLE
/* Return the completion status. */
status = thread_ptr -> tx_thread_suspend_status;
#endif
}
}
else
{
/* Immediate return, return error completion. */
status = TX_NO_EVENTS;
}
}
/* Restore interrupts. */
TX_RESTORE
/* Return completion status. */
return(status);
}
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