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; 23;#define TX_SOURCE_CODE 24; 25; 26;/* Include necessary system files. */ 27; 28;#include "tx_api.h" 29;#include "tx_thread.h" 30;#include "tx_timer.h" 31; 32#ifdef TX_ENABLE_FIQ_SUPPORT 33ENABLE_INTS DEFINE 0xC0 ; IRQ & FIQ Interrupts enabled mask 34#else 35ENABLE_INTS DEFINE 0x80 ; IRQ Interrupts enabled mask 36#endif 37; 38; 39 EXTERN _tx_thread_execute_ptr 40 EXTERN _tx_thread_current_ptr 41 EXTERN _tx_timer_time_slice 42 EXTERN _tx_execution_thread_enter 43; 44; 45; 46;/**************************************************************************/ 47;/* */ 48;/* FUNCTION RELEASE */ 49;/* */ 50;/* _tx_thread_schedule ARM9/IAR */ 51;/* 6.1 */ 52;/* AUTHOR */ 53;/* */ 54;/* William E. Lamie, Microsoft Corporation */ 55;/* */ 56;/* DESCRIPTION */ 57;/* */ 58;/* This function waits for a thread control block pointer to appear in */ 59;/* the _tx_thread_execute_ptr variable. Once a thread pointer appears */ 60;/* in the variable, the corresponding thread is resumed. */ 61;/* */ 62;/* INPUT */ 63;/* */ 64;/* None */ 65;/* */ 66;/* OUTPUT */ 67;/* */ 68;/* None */ 69;/* */ 70;/* CALLS */ 71;/* */ 72;/* None */ 73;/* */ 74;/* CALLED BY */ 75;/* */ 76;/* _tx_initialize_kernel_enter ThreadX entry function */ 77;/* _tx_thread_system_return Return to system from thread */ 78;/* _tx_thread_context_restore Restore thread's context */ 79;/* */ 80;/* RELEASE HISTORY */ 81;/* */ 82;/* DATE NAME DESCRIPTION */ 83;/* */ 84;/* 09-30-2020 William E. Lamie Initial Version 6.1 */ 85;/* */ 86;/**************************************************************************/ 87;VOID _tx_thread_schedule(VOID) 88;{ 89 RSEG .text:CODE:NOROOT(2) 90 PUBLIC _tx_thread_schedule 91 CODE32 92_tx_thread_schedule??rA 93_tx_thread_schedule 94; 95; /* Enable interrupts. */ 96; 97 MRS r2, CPSR ; Pickup CPSR 98 BIC r0, r2, #ENABLE_INTS ; Clear the disable bit(s) 99 MSR CPSR_cxsf, r0 ; Enable interrupts 100; 101; /* Wait for a thread to execute. */ 102; do 103; { 104 LDR r1, =_tx_thread_execute_ptr ; Address of thread execute ptr 105; 106__tx_thread_schedule_loop 107; 108 LDR r0, [r1, #0] ; Pickup next thread to execute 109 CMP r0, #0 ; Is it NULL? 110 BEQ __tx_thread_schedule_loop ; If so, keep looking for a thread 111; 112; } 113; while(_tx_thread_execute_ptr == TX_NULL); 114; 115; /* Yes! We have a thread to execute. Lockout interrupts and 116; transfer control to it. */ 117; 118 MSR CPSR_cxsf, r2 ; Disable interrupts 119; 120; /* Setup the current thread pointer. */ 121; _tx_thread_current_ptr = _tx_thread_execute_ptr; 122; 123 LDR r1, =_tx_thread_current_ptr ; Pickup address of current thread 124 STR r0, [r1, #0] ; Setup current thread pointer 125; 126; /* Increment the run count for this thread. */ 127; _tx_thread_current_ptr -> tx_thread_run_count++; 128; 129 LDR r2, [r0, #4] ; Pickup run counter 130 LDR r3, [r0, #24] ; Pickup time-slice for this thread 131 ADD r2, r2, #1 ; Increment thread run-counter 132 STR r2, [r0, #4] ; Store the new run counter 133; 134; /* Setup time-slice, if present. */ 135; _tx_timer_time_slice = _tx_thread_current_ptr -> tx_thread_time_slice; 136; 137 LDR r2, =_tx_timer_time_slice ; Pickup address of time slice 138 ; variable 139 LDR sp, [r0, #8] ; Switch stack pointers 140 STR r3, [r2, #0] ; Setup time-slice 141; 142; /* Switch to the thread's stack. */ 143; sp = _tx_thread_execute_ptr -> tx_thread_stack_ptr; 144; 145#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY 146; 147; /* Call the thread entry function to indicate the thread is executing. */ 148; 149 BL _tx_execution_thread_enter ; Call the thread execution enter function 150#endif 151; 152; /* Determine if an interrupt frame or a synchronous task suspension frame 153; is present. */ 154; 155 LDMIA sp!, {r0, r1} ; Pickup the stack type and saved CPSR 156 CMP r0, #0 ; Check for synchronous context switch 157 MSRNE SPSR_cxsf, r1 ; Setup SPSR for return 158 LDMNEIA sp!, {r0-r12, lr, pc}^ ; Return to point of thread interrupt 159 LDMIA sp!, {r4-r11, lr} ; Return to thread synchronously 160 MSR CPSR_cxsf, r1 ; Recover CPSR 161#ifdef TX_THUMB 162 BX lr ; Return to caller 163#else 164 MOV pc, lr ; Return to caller 165#endif 166; 167;} 168; 169 END 170 171
