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;/***************************************************************************
; * Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2026-present Eclipse ThreadX contributors
; *
; * 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"
;
;
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 Cortex-A9/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. */
;
IF :DEF:TX_ENABLE_FIQ_SUPPORT
CPSIE if ; Enable IRQ and FIQ interrupts
ELSE
CPSIE i ; Enable IRQ interrupts
ENDIF
;
; /* 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. */
;
IF :DEF:TX_ENABLE_FIQ_SUPPORT
CPSID if ; Enable IRQ and FIQ interrupts
ELSE
CPSID i ; Enable IRQ interrupts
ENDIF
;
; /* 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
IF :DEF:TX_ENABLE_EXECUTION_CHANGE_NOTIFY
;
; /* Call the thread entry function to indicate the thread is executing. */
;
MOV r5, r0 ; Save r0
BL _tx_execution_thread_enter ; Call the thread execution enter function
MOV r0, r5 ; Restore r0
ENDIF
;
; /* Switch to the thread's stack. */
; sp = _tx_thread_execute_ptr -> tx_thread_stack_ptr;
;
; /* Determine if an interrupt frame or a synchronous task suspension frame
; is present. */
;
LDMIA sp!, {r4, r5} ; Pickup the stack type and saved CPSR
CMP r4, #0 ; Check for synchronous context switch
BEQ _tx_solicited_return
MSR SPSR_cxsf, r5 ; Setup SPSR for return
IF {TARGET_FPU_VFP} = {TRUE}
LDR r1, [r0, #144] ; Pickup the VFP enabled flag
CMP r1, #0 ; Is the VFP enabled?
BEQ _tx_skip_interrupt_vfp_restore ; No, skip VFP interrupt restore
VLDMIA sp!, {D0-D15} ; Recover D0-D15
VLDMIA sp!, {D16-D31} ; Recover D16-D31
LDR r4, [sp], #4 ; Pickup FPSCR
VMSR FPSCR, r4 ; Restore FPSCR
_tx_skip_interrupt_vfp_restore
ENDIF
LDMIA sp!, {r0-r12, lr, pc}^ ; Return to point of thread interrupt
_tx_solicited_return
IF {TARGET_FPU_VFP} = {TRUE}
LDR r1, [r0, #144] ; Pickup the VFP enabled flag
CMP r1, #0 ; Is the VFP enabled?
BEQ _tx_skip_solicited_vfp_restore ; No, skip VFP solicited restore
VLDMIA sp!, {D8-D15} ; Recover D8-D15
VLDMIA sp!, {D16-D31} ; Recover D16-D31
LDR r4, [sp], #4 ; Pickup FPSCR
VMSR FPSCR, r4 ; Restore FPSCR
_tx_skip_solicited_vfp_restore
ENDIF
MSR CPSR_cxsf, r5 ; Recover CPSR
LDMIA sp!, {r4-r11, lr} ; Return to thread synchronously
IF {INTER} = {TRUE}
BX lr ; Return to caller
ELSE
MOV pc, lr ; Return to caller
ENDIF
;
;}
;
IF {TARGET_FPU_VFP} = {TRUE}
EXPORT tx_thread_vfp_enable
tx_thread_vfp_enable
MRS r2, CPSR ; Pickup the CPSR
IF :DEF:TX_ENABLE_FIQ_SUPPORT
CPSID if ; Disable IRQ and FIQ interrupts
ELSE
CPSID i ; Disable IRQ interrupts
ENDIF
LDR r0, =_tx_thread_current_ptr ; Build current thread pointer address
LDR r1, [r0] ; Pickup current thread pointer
CMP r1, #0 ; Check for NULL thread pointer
BEQ __tx_no_thread_to_enable ; If NULL, skip VFP enable
MOV r0, #1 ; Build enable value
STR r0, [r1, #144] ; Set the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD)
__tx_no_thread_to_enable
MSR CPSR_cxsf, r2 ; Recover CPSR
BX LR ; Return to caller
EXPORT tx_thread_vfp_disable
tx_thread_vfp_disable
MRS r2, CPSR ; Pickup the CPSR
IF :DEF:TX_ENABLE_FIQ_SUPPORT
CPSID if ; Disable IRQ and FIQ interrupts
ELSE
CPSID i ; Disable IRQ interrupts
ENDIF
LDR r0, =_tx_thread_current_ptr ; Build current thread pointer address
LDR r1, [r0] ; Pickup current thread pointer
CMP r1, #0 ; Check for NULL thread pointer
BEQ __tx_no_thread_to_disable ; If NULL, skip VFP disable
MOV r0, #0 ; Build disable value
STR r0, [r1, #144] ; Clear the VFP enable flag (tx_thread_vfp_enable field in TX_THREAD)
__tx_no_thread_to_disable
MSR CPSR_cxsf, r2 ; Recover CPSR
BX LR ; Return to caller
ENDIF
END
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