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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 */
@/** */
@/**************************************************************************/
@/**************************************************************************/
#ifdef TX_INCLUDE_USER_DEFINE_FILE
#include "tx_user.h"
#endif
#ifdef TX_ENABLE_FIQ_SUPPORT
DISABLE_INTS = 0xC0 @ IRQ & FIQ interrupts disabled
#else
DISABLE_INTS = 0x80 @ IRQ interrupts disabled
#endif
@
.global _tx_thread_system_state
.global _tx_thread_current_ptr
.global _tx_irq_processing_return
.global _tx_execution_isr_enter
@
@
@/* No 16-bit Thumb mode veneer code is needed for _tx_thread_context_save
@ since it will never be called 16-bit mode. */
@
.arm
.text
.align 2
@/**************************************************************************/
@/* */
@/* FUNCTION RELEASE */
@/* */
@/* _tx_thread_context_save ARM9/GNU */
@/* 6.2.1 */
@/* AUTHOR */
@/* */
@/* William E. Lamie, Microsoft Corporation */
@/* */
@/* DESCRIPTION */
@/* */
@/* This function saves the context of an executing thread in the */
@/* beginning of interrupt processing. The function also ensures that */
@/* the system stack is used upon return to the calling ISR. */
@/* */
@/* INPUT */
@/* */
@/* None */
@/* */
@/* OUTPUT */
@/* */
@/* None */
@/* */
@/* CALLS */
@/* */
@/* None */
@/* */
@/* CALLED BY */
@/* */
@/* ISRs */
@/* */
@/**************************************************************************/
@VOID _tx_thread_context_save(VOID)
@{
.global _tx_thread_context_save
.type _tx_thread_context_save,function
_tx_thread_context_save:
@
@ /* Upon entry to this routine, it is assumed that IRQ interrupts are locked
@ out, we are in IRQ mode, and all registers are intact. */
@
@ /* Check for a nested interrupt condition. */
@ if (_tx_thread_system_state++)
@ {
@
STMDB sp!, {r0-r3} @ Save some working registers
#ifdef TX_ENABLE_FIQ_SUPPORT
MRS r0, CPSR @ Pickup the CPSR
ORR r0, r0, #DISABLE_INTS @ Build disable interrupt CPSR
MSR CPSR_cxsf, r0 @ Disable interrupts
#endif
LDR r3, =_tx_thread_system_state @ Pickup address of system state variable
LDR r2, [r3] @ Pickup system state
CMP r2, #0 @ Is this the first interrupt?
BEQ __tx_thread_not_nested_save @ Yes, not a nested context save
@
@ /* Nested interrupt condition. */
@
ADD r2, r2, #1 @ Increment the interrupt counter
STR r2, [r3] @ Store it back in the variable
@
@ /* Save the rest of the scratch registers on the stack and return to the
@ calling ISR. */
@
MRS r0, SPSR @ Pickup saved SPSR
SUB lr, lr, #4 @ Adjust point of interrupt
STMDB sp!, {r0, r10, r12, lr} @ Store other registers
@
@ /* Return to the ISR. */
@
MOV r10, #0 @ Clear stack limit
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
@
@ /* Call the ISR enter function to indicate an ISR is executing. */
@
PUSH {lr} @ Save ISR lr
BL _tx_execution_isr_enter @ Call the ISR enter function
POP {lr} @ Recover ISR lr
#endif
B __tx_irq_processing_return @ Continue IRQ processing
@
__tx_thread_not_nested_save:
@ }
@
@ /* Otherwise, not nested, check to see if a thread was running. */
@ else if (_tx_thread_current_ptr)
@ {
@
ADD r2, r2, #1 @ Increment the interrupt counter
STR r2, [r3] @ Store it back in the variable
LDR r1, =_tx_thread_current_ptr @ Pickup address of current thread ptr
LDR r0, [r1] @ Pickup current thread pointer
CMP r0, #0 @ Is it NULL?
BEQ __tx_thread_idle_system_save @ If so, interrupt occurred in
@ scheduling loop - nothing needs saving!
@
@ /* Save minimal context of interrupted thread. */
@
MRS r2, SPSR @ Pickup saved SPSR
SUB lr, lr, #4 @ Adjust point of interrupt
STMDB sp!, {r2, r10, r12, lr} @ Store other registers
@
@ /* Save the current stack pointer in the thread's control block. */
@ _tx_thread_current_ptr -> tx_thread_stack_ptr = sp;
@
@ /* Switch to the system stack. */
@ sp = _tx_thread_system_stack_ptr@
@
MOV r10, #0 @ Clear stack limit
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
@
@ /* Call the ISR enter function to indicate an ISR is executing. */
@
PUSH {lr} @ Save ISR lr
BL _tx_execution_isr_enter @ Call the ISR enter function
POP {lr} @ Recover ISR lr
#endif
B __tx_irq_processing_return @ Continue IRQ processing
@
@ }
@ else
@ {
@
__tx_thread_idle_system_save:
@
@ /* Interrupt occurred in the scheduling loop. */
@
@ /* Not much to do here, just adjust the stack pointer, and return to IRQ
@ processing. */
@
MOV r10, #0 @ Clear stack limit
#ifdef TX_ENABLE_EXECUTION_CHANGE_NOTIFY
@
@ /* Call the ISR enter function to indicate an ISR is executing. */
@
PUSH {lr} @ Save ISR lr
BL _tx_execution_isr_enter @ Call the ISR enter function
POP {lr} @ Recover ISR lr
#endif
ADD sp, sp, #16 @ Recover saved registers
B __tx_irq_processing_return @ Continue IRQ processing
@
@ }
@}
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