;/*
; * FreeRTOS Kernel V10.6.2
; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
; *
; * SPDX-License-Identifier: MIT
; *
; * Permission is hereby granted, free of charge, to any person obtaining a copy of
; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
; * the Software, and to permit persons to whom the Software is furnished to do so,
; * subject to the following conditions:
; *
; * The above copyright notice and this permission notice shall be included in all
; * copies or substantial portions of the Software.
; *
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
; *
; * https://www.FreeRTOS.org
; * https://github.com/FreeRTOS
; *
; */
        RSEG ICODE:CODE
        CODE32

    EXTERN vTaskSwitchContext
    EXTERN xTaskIncrementTick

    PUBLIC vPortYieldProcessor
    PUBLIC vPortPreemptiveTick
    PUBLIC vPortStartFirstTask

#include "AT91SAM7S64_inc.h"
#include "ISR_Support.h"

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Starting the first task is just a matter of restoring the context that
; was created by pxPortInitialiseStack().
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortStartFirstTask:
    portRESTORE_CONTEXT

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Manual context switch function.  This is the SWI hander.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortYieldProcessor:
    ADD     LR, LR, #4          ; Add 4 to the LR to make the LR appear exactly
                                ; as if the context was saved during and IRQ
                                ; handler.

    portSAVE_CONTEXT            ; Save the context of the current task...
    LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
    mov     lr, pc
    BX R0
    portRESTORE_CONTEXT         ; Restore the context of the selected task.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Preemptive context switch function.  This will only ever get installed if
; portUSE_PREEMPTION is set to 1 in portmacro.h.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortPreemptiveTick:
    portSAVE_CONTEXT            ; Save the context of the current task.

    LDR R0, =xTaskIncrementTick ; Increment the tick count - this may wake a task.
    mov lr, pc
    BX R0

    CMP R0, #0
    BEQ SkipContextSwitch
    LDR R0, =vTaskSwitchContext ; Select the next task to execute.
    mov lr, pc
    BX R0
SkipContextSwitch
    LDR R14, =AT91C_BASE_PITC   ; Clear the PIT interrupt
    LDR R0, [R14, #PITC_PIVR ]

    LDR R14, =AT91C_BASE_AIC    ; Mark the End of Interrupt on the AIC
    STR R14, [R14, #AIC_EOICR]

    portRESTORE_CONTEXT         ; Restore the context of the selected task.


    END