1 /*************************************************************************** 2 * Copyright (c) 2024 Microsoft Corporation 3 * 4 * This program and the accompanying materials are made available under the 5 * terms of the MIT License which is available at 6 * https://opensource.org/licenses/MIT. 7 * 8 * SPDX-License-Identifier: MIT 9 **************************************************************************/ 10 11 12 /**************************************************************************/ 13 /**************************************************************************/ 14 /** */ 15 /** ThreadX Component */ 16 /** */ 17 /** Thread */ 18 /** */ 19 /**************************************************************************/ 20 /**************************************************************************/ 21 22 #define TX_SOURCE_CODE 23 24 25 /* Include necessary system files. */ 26 27 #include "tx_api.h" 28 #include "tx_thread.h" 29 30 31 /**************************************************************************/ 32 /* */ 33 /* FUNCTION RELEASE */ 34 /* */ 35 /* _tx_thread_system_preempt_check PORTABLE C */ 36 /* 6.1 */ 37 /* AUTHOR */ 38 /* */ 39 /* William E. Lamie, Microsoft Corporation */ 40 /* */ 41 /* DESCRIPTION */ 42 /* */ 43 /* This function checks for preemption that could have occurred as a */ 44 /* result scheduling activities occurring while the preempt disable */ 45 /* flag was set. */ 46 /* */ 47 /* INPUT */ 48 /* */ 49 /* None */ 50 /* */ 51 /* OUTPUT */ 52 /* */ 53 /* None */ 54 /* */ 55 /* CALLS */ 56 /* */ 57 /* _tx_thread_system_return Return to the system */ 58 /* */ 59 /* CALLED BY */ 60 /* */ 61 /* Other ThreadX Components */ 62 /* */ 63 /* RELEASE HISTORY */ 64 /* */ 65 /* DATE NAME DESCRIPTION */ 66 /* */ 67 /* 05-19-2020 William E. Lamie Initial Version 6.0 */ 68 /* 09-30-2020 Yuxin Zhou Modified comment(s), */ 69 /* resulting in version 6.1 */ 70 /* */ 71 /**************************************************************************/ _tx_thread_system_preempt_check(VOID)72VOID _tx_thread_system_preempt_check(VOID) 73 { 74 75 ULONG combined_flags; 76 TX_THREAD *current_thread; 77 TX_THREAD *thread_ptr; 78 79 80 /* Combine the system state and preempt disable flags into one for comparison. */ 81 TX_THREAD_SYSTEM_RETURN_CHECK(combined_flags) 82 83 /* Determine if we are in a system state (ISR or Initialization) or internal preemption is disabled. */ 84 if (combined_flags == ((ULONG) 0)) 85 { 86 87 /* No, at thread execution level so continue checking for preemption. */ 88 89 /* Pickup thread pointer. */ 90 TX_THREAD_GET_CURRENT(current_thread) 91 92 /* Pickup the next execute pointer. */ 93 thread_ptr = _tx_thread_execute_ptr; 94 95 /* Determine if preemption should take place. */ 96 if (current_thread != thread_ptr) 97 { 98 99 #ifdef TX_ENABLE_STACK_CHECKING 100 101 /* Check this thread's stack. */ 102 TX_THREAD_STACK_CHECK(thread_ptr) 103 #endif 104 105 106 #ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO 107 108 /* Determine if an idle system return is present. */ 109 if (thread_ptr == TX_NULL) 110 { 111 112 /* Yes, increment the return to idle return count. */ 113 _tx_thread_performance_idle_return_count++; 114 } 115 else 116 { 117 118 /* No, there is another thread ready to run and will be scheduled upon return. */ 119 _tx_thread_performance_non_idle_return_count++; 120 } 121 #endif 122 123 /* Return to the system so the higher priority thread can be scheduled. */ 124 _tx_thread_system_return(); 125 } 126 } 127 } 128 129
