1;/**************************************************************************/ 2;/* */ 3;/* Copyright (c) Microsoft Corporation. All rights reserved. */ 4;/* */ 5;/* This software is licensed under the Microsoft Software License */ 6;/* Terms for Microsoft Azure RTOS. Full text of the license can be */ 7;/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */ 8;/* and in the root directory of this software. */ 9;/* */ 10;/**************************************************************************/ 11; 12; 13;/**************************************************************************/ 14;/**************************************************************************/ 15;/** */ 16;/** ThreadX Component */ 17;/** */ 18;/** Thread */ 19;/** */ 20;/**************************************************************************/ 21;/**************************************************************************/ 22; 23; 24;#define TX_SOURCE_CODE 25; 26; 27;/* Include necessary system files. */ 28; 29;#include "tx_api.h" 30;#include "tx_thread.h" 31;#include "tx_timer.h" 32; 33#ifdef TX_ENABLE_FIQ_SUPPORT 34ENABLE_INTS DEFINE 0xC0 ; IRQ & FIQ Interrupts enabled mask 35#else 36ENABLE_INTS DEFINE 0x80 ; IRQ Interrupts enabled mask 37#endif 38; 39; 40 EXTERN _tx_thread_execute_ptr 41 EXTERN _tx_thread_current_ptr 42 EXTERN _tx_timer_time_slice 43 EXTERN _tx_execution_thread_enter 44; 45; 46; 47;/**************************************************************************/ 48;/* */ 49;/* FUNCTION RELEASE */ 50;/* */ 51;/* _tx_thread_schedule ARM11/IAR */ 52;/* 6.1 */ 53;/* AUTHOR */ 54;/* */ 55;/* William E. Lamie, Microsoft Corporation */ 56;/* */ 57;/* DESCRIPTION */ 58;/* */ 59;/* This function waits for a thread control block pointer to appear in */ 60;/* the _tx_thread_execute_ptr variable. Once a thread pointer appears */ 61;/* in the variable, the corresponding thread is resumed. */ 62;/* */ 63;/* INPUT */ 64;/* */ 65;/* None */ 66;/* */ 67;/* OUTPUT */ 68;/* */ 69;/* None */ 70;/* */ 71;/* CALLS */ 72;/* */ 73;/* None */ 74;/* */ 75;/* CALLED BY */ 76;/* */ 77;/* _tx_initialize_kernel_enter ThreadX entry function */ 78;/* _tx_thread_system_return Return to system from thread */ 79;/* _tx_thread_context_restore Restore thread's context */ 80;/* */ 81;/* RELEASE HISTORY */ 82;/* */ 83;/* DATE NAME DESCRIPTION */ 84;/* */ 85;/* 09-30-2020 William E. Lamie Initial Version 6.1 */ 86;/* */ 87;/**************************************************************************/ 88;VOID _tx_thread_schedule(VOID) 89;{ 90 RSEG .text:CODE:NOROOT(2) 91 PUBLIC _tx_thread_schedule 92 CODE32 93_tx_thread_schedule??rA 94_tx_thread_schedule 95; 96; /* Enable interrupts. */ 97; 98 MRS r2, CPSR ; Pickup CPSR 99 BIC r0, r2, #ENABLE_INTS ; Clear the disable bit(s) 100 MSR CPSR_cxsf, r0 ; Enable interrupts 101; 102; /* Wait for a thread to execute. */ 103; do 104; { 105 LDR r1, =_tx_thread_execute_ptr ; Address of thread execute ptr 106; 107__tx_thread_schedule_loop 108; 109 LDR r0, [r1, #0] ; Pickup next thread to execute 110 CMP r0, #0 ; Is it NULL? 111 BEQ __tx_thread_schedule_loop ; If so, keep looking for a thread 112; 113; } 114; while(_tx_thread_execute_ptr == TX_NULL); 115; 116; /* Yes! We have a thread to execute. Lockout interrupts and 117; transfer control to it. */ 118; 119 MSR CPSR_cxsf, r2 ; Disable interrupts 120; 121; /* Setup the current thread pointer. */ 122; _tx_thread_current_ptr = _tx_thread_execute_ptr; 123; 124 LDR r1, =_tx_thread_current_ptr ; Pickup address of current thread 125 STR r0, [r1, #0] ; Setup current thread pointer 126; 127; /* Increment the run count for this thread. */ 128; _tx_thread_current_ptr -> tx_thread_run_count++; 129; 130 LDR r2, [r0, #4] ; Pickup run counter 131 LDR r3, [r0, #24] ; Pickup time-slice for this thread 132 ADD r2, r2, #1 ; Increment thread run-counter 133 STR r2, [r0, #4] ; Store the new run counter 134; 135; /* Setup time-slice, if present. */ 136; _tx_timer_time_slice = _tx_thread_current_ptr -> tx_thread_time_slice; 137; 138 LDR r2, =_tx_timer_time_slice ; Pickup address of time slice 139 ; variable 140 LDR sp, [r0, #8] ; Switch stack pointers 141 STR r3, [r2, #0] ; Setup time-slice 142; 143; /* Switch to the thread's stack. */ 144; sp = _tx_thread_execute_ptr -> tx_thread_stack_ptr; 145; 146#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY 147; 148; /* Call the thread entry function to indicate the thread is executing. */ 149; 150 BL _tx_execution_thread_enter ; Call the thread execution enter function 151#endif 152; 153; /* Determine if an interrupt frame or a synchronous task suspension frame 154; is present. */ 155; 156 LDMIA sp!, {r0, r1} ; Pickup the stack type and saved CPSR 157 CMP r0, #0 ; Check for synchronous context switch 158 MSRNE SPSR_cxsf, r1 ; Setup SPSR for return 159 LDMNEIA sp!, {r0-r12, lr, pc}^ ; Return to point of thread interrupt 160 LDMIA sp!, {r4-r11, lr} ; Return to thread synchronously 161 MSR CPSR_cxsf, r1 ; Recover CPSR 162#ifdef TX_THUMB 163 BX lr ; Return to caller 164#else 165 MOV pc, lr ; Return to caller 166#endif 167; 168;} 169; 170 END 171 172
