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|
;/***************************************************************************
; * Copyright (c) 2024 Microsoft Corporation
; *
; * 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.
; *
; * SPDX-License-Identifier: MIT
; **************************************************************************/
;
;
;/**************************************************************************/
;/**************************************************************************/
;/** */
;/** ThreadX Component */
;/** */
;/** Thread */
;/** */
;/**************************************************************************/
;/**************************************************************************/
;
;
;#define TX_SOURCE_CODE
;
;
;/* Include necessary system files. */
;
;#include "tx_api.h"
;#include "tx_thread.h"
;#include "tx_timer.h"
;
;
IF :DEF:TX_ENABLE_FIQ_SUPPORT
ENABLE_INTS EQU 0xC0 ; IRQ & FIQ Interrupts enabled mask
ELSE
ENABLE_INTS EQU 0x80 ; IRQ Interrupts enabled mask
ENDIF
;
;
IMPORT _tx_thread_execute_ptr
IMPORT _tx_thread_current_ptr
IMPORT _tx_timer_time_slice
IF :DEF:TX_ENABLE_EXECUTION_CHANGE_NOTIFY
IMPORT _tx_execution_thread_enter
ENDIF
;
;
AREA ||.text||, CODE, READONLY
PRESERVE8
;/**************************************************************************/
;/* */
;/* FUNCTION RELEASE */
;/* */
;/* _tx_thread_schedule ARM11/AC5 */
;/* 6.1 */
;/* AUTHOR */
;/* */
;/* William E. Lamie, Microsoft Corporation */
;/* */
;/* DESCRIPTION */
;/* */
;/* This function waits for a thread control block pointer to appear in */
;/* the _tx_thread_execute_ptr variable. Once a thread pointer appears */
;/* in the variable, the corresponding thread is resumed. */
;/* */
;/* INPUT */
;/* */
;/* None */
;/* */
;/* OUTPUT */
;/* */
;/* None */
;/* */
;/* CALLS */
;/* */
;/* None */
;/* */
;/* CALLED BY */
;/* */
;/* _tx_initialize_kernel_enter ThreadX entry function */
;/* _tx_thread_system_return Return to system from thread */
;/* _tx_thread_context_restore Restore thread's context */
;/* */
;/**************************************************************************/
;VOID _tx_thread_schedule(VOID)
;{
EXPORT _tx_thread_schedule
_tx_thread_schedule
;
; /* Enable interrupts. */
;
MRS r2, CPSR ; Pickup CPSR
BIC r0, r2, #ENABLE_INTS ; Clear the disable bit(s)
MSR CPSR_cxsf, r0 ; Enable interrupts
;
; /* Wait for a thread to execute. */
; do
; {
LDR r1, =_tx_thread_execute_ptr ; Address of thread execute ptr
;
__tx_thread_schedule_loop
;
LDR r0, [r1, #0] ; Pickup next thread to execute
CMP r0, #0 ; Is it NULL?
BEQ __tx_thread_schedule_loop ; If so, keep looking for a thread
;
; }
; while(_tx_thread_execute_ptr == TX_NULL);
;
; /* Yes! We have a thread to execute. Lockout interrupts and
; transfer control to it. */
;
MSR CPSR_cxsf, r2 ; Disable interrupts
;
; /* Setup the current thread pointer. */
; _tx_thread_current_ptr = _tx_thread_execute_ptr;
;
LDR r1, =_tx_thread_current_ptr ; Pickup address of current thread
STR r0, [r1, #0] ; Setup current thread pointer
;
; /* Increment the run count for this thread. */
; _tx_thread_current_ptr -> tx_thread_run_count++;
;
LDR r2, [r0, #4] ; Pickup run counter
LDR r3, [r0, #24] ; Pickup time-slice for this thread
ADD r2, r2, #1 ; Increment thread run-counter
STR r2, [r0, #4] ; Store the new run counter
;
; /* Setup time-slice, if present. */
; _tx_timer_time_slice = _tx_thread_current_ptr -> tx_thread_time_slice;
;
LDR r2, =_tx_timer_time_slice ; Pickup address of time slice
; variable
LDR sp, [r0, #8] ; Switch stack pointers
STR r3, [r2, #0] ; Setup time-slice
;
; /* Switch to the thread's stack. */
; sp = _tx_thread_execute_ptr -> tx_thread_stack_ptr;
;
IF :DEF:TX_ENABLE_EXECUTION_CHANGE_NOTIFY
;
; /* Call the thread entry function to indicate the thread is executing. */
;
BL _tx_execution_thread_enter ; Call the thread execution enter function
ENDIF
;
; /* Determine if an interrupt frame or a synchronous task suspension frame
; is present. */
;
LDMIA sp!, {r0, r1} ; Pickup the stack type and saved CPSR
CMP r0, #0 ; Check for synchronous context switch
MSRNE SPSR_cxsf, r1 ; Setup SPSR for return
LDMNEIA sp!, {r0-r12, lr, pc}^ ; Return to point of thread interrupt
LDMIA sp!, {r4-r11, lr} ; Return to thread synchronously
MSR CPSR_cxsf, r1 ; Recover CPSR
IF {INTER} = {TRUE}
BX lr ; Return to caller
ELSE
MOV pc, lr ; Return to caller
ENDIF
;
;}
;
END
|
