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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"
;
;
#ifdef TX_ENABLE_FIQ_SUPPORT
DISABLE_INTS DEFINE 0xC0 ; IRQ & FIQ interrupts disabled
#else
DISABLE_INTS DEFINE 0x80 ; IRQ interrupts disabled
#endif
EXTERN _tx_thread_system_state
EXTERN _tx_thread_current_ptr
EXTERN __tx_irq_processing_return
EXTERN _tx_execution_isr_enter
;
;
;/**************************************************************************/
;/* */
;/* FUNCTION RELEASE */
;/* */
;/* _tx_thread_context_save ARM11/IAR */
;/* 6.1 */
;/* 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)
;{
RSEG .text:CODE:NOROOT(2)
PUBLIC _tx_thread_context_save
CODE32
_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 var
LDR r2, [r3, #0] ; 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, #0] ; 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, #0] ; Store it back in the variable
LDR r1, =_tx_thread_current_ptr ; Pickup address of current thread ptr
LDR r0, [r1, #0] ; Pickup current thread pointer
CMP r0, #0 ; Is it NULL?
BEQ __tx_thread_idle_system_save ; If so, interrupt occured 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
;
; }
;}
;
;
;
END
|
