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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"
;
;
.global __tx_thread_system_state
.global __tx_thread_current_ptr
.global __tx_thread_system_stack_ptr
.global __tx_thread_execute_ptr
.global __tx_timer_time_slice
.global __tx_thread_schedule
.global __tx_thread_preempt_disable
.text
;/**************************************************************************/
;/* */
;/* FUNCTION RELEASE */
;/* */
;/* _tx_thread_context_restore RXv2/GNURX */
;/* 6.1.11 */
;/* AUTHOR */
;/* */
;/* William E. Lamie, Microsoft Corporation */
;/* */
;/* DESCRIPTION */
;/* */
;/* This function restores the interrupt context if it is processing a */
;/* nested interrupt. If not, it returns to the interrupt thread if no */
;/* preemption is necessary. Otherwise, if preemption is necessary or */
;/* if no thread was running, the function returns to the scheduler. */
;/* */
;/* INPUT */
;/* */
;/* None */
;/* */
;/* OUTPUT */
;/* */
;/* None */
;/* */
;/* CALLS */
;/* */
;/* _tx_thread_schedule Thread scheduling routine */
;/* */
;/* CALLED BY */
;/* */
;/* ISRs Interrupt Service Routines */
;/* */
;/**************************************************************************/
;VOID _tx_thread_context_restore(VOID)
;{
.global __tx_thread_context_restore
__tx_thread_context_restore:
;
; /* Lockout interrupts. */
CLRPSW I ; Disable interrupts
; /* Determine if interrupts are nested. */
; if (--_tx_thread_system_state)
; {
MOV.L #__tx_thread_system_state, R1
MOV.L [R1], R2
SUB #1, R2
MOV.L R2,[R1]
BEQ __tx_thread_not_nested_restore
;
; /* Interrupts are nested. */
;
; /* Recover the saved registers from the interrupt stack
; and return to the point of interrupt. */
;
__tx_thread_nested_restore:
POPC FPSW ; Restore FPU status
POPM R14-R15 ; Restore R14-R15
POPM R3-R5 ; Restore R3-R5
POPM R1-R2 ; Restore R1-R2
RTE ; Return to point of interrupt, restore PSW including IPL
; }
__tx_thread_not_nested_restore:
;
; /* Determine if a thread was interrupted and no preemption is required. */
; else if (((_tx_thread_current_ptr) && (_tx_thread_current_ptr == _tx_thread_execute_ptr)
; || (_tx_thread_preempt_disable))
; {
MOV.L #__tx_thread_current_ptr, R1 ; Pickup current thread ptr address
MOV.L [R1], R2
CMP #0, R2
BEQ __tx_thread_idle_system_restore
MOV.L #__tx_thread_preempt_disable, R3 ; Pick up preempt disable flag
MOV.L [R3], R3
CMP #0, R3
BNE __tx_thread_no_preempt_restore ; If pre-empt disable flag set, we simply return to the original point of interrupt regardless
MOV.L #__tx_thread_execute_ptr, R3 ; (_tx_thread_current_ptr != _tx_thread_execute_ptr)
CMP [R3], R2
BNE __tx_thread_preempt_restore ; Jump to pre-empt restoring
;
__tx_thread_no_preempt_restore:
SETPSW U ; User stack
POPC FPSW ; Restore FPU status
POPM R14-R15 ; Restore R14-R15
POPM R3-R5 ; Restore R3-R5
POPM R1-R2 ; Restore R1-R2
RTE ; Return to point of interrupt, restore PSW including IPL
; }
; else
; {
__tx_thread_preempt_restore:
; /* Save the remaining time-slice and disable it. */
; if (_tx_timer_time_slice)
; {
MOV.L #__tx_timer_time_slice, R3 ; Pickup time-slice address
MOV.L [R3],R4 ; Pickup actual time-slice
CMP #0, R4
BEQ __tx_thread_dont_save_ts ; No time slice to save
;
; _tx_thread_current_ptr -> tx_thread_time_slice = _tx_timer_time_slice;
; _tx_timer_time_slice = 0;
;
MOV.L R4,24[R2] ; Save thread's time slice
MOV.L #0,R4 ; Clear value
MOV.L R4,[R3] ; Disable global time slice flag
; }
__tx_thread_dont_save_ts:
;
; /* Now store the remaining registers! */
SETPSW U ; User stack
PUSHM R6-R13
MVFACGU #0, A1, R4 ; Save accumulators.
MVFACHI #0, A1, R5
MVFACLO #0, A1, R6
PUSHM R4-R6
MVFACGU #0, A0, R4
MVFACHI #0, A0, R5
MVFACLO #0, A0, R6
PUSHM R4-R6
;
; /* Clear the current task pointer. */
; _tx_thread_current_ptr = TX_NULL;
; R1 -> _tx_thread_current_ptr
; R2 -> *_tx_thread_current_ptr
MOV.L R0,8[R2] ; Save thread's stack pointer in thread control block
MOV.L #0,R2 ; Build NULL value
MOV.L R2,[R1] ; Set current thread to NULL
; /* Return to the scheduler. */
; _tx_thread_schedule();
__tx_thread_idle_system_restore:
MVTC #0, PSW ; Reset interrupt priority level to 0
BRA __tx_thread_schedule ; Jump to scheduler
; }
;
;}
;
.end
|
