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;/*
; * FreeRTOS Kernel <DEVELOPMENT BRANCH>
; * 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
; *
; */
.thumb
.ref pxCurrentTCB
.ref vTaskSwitchContext
.ref ulMaxSyscallInterruptPriority
.def xPortPendSVHandler
.def ulPortGetIPSR
.def vPortSVCHandler
.def vPortStartFirstTask
NVICOffsetConst: .word 0xE000ED08
CPACRConst: .word 0xE000ED88
pxCurrentTCBConst: .word pxCurrentTCB
ulMaxSyscallInterruptPriorityConst: .word ulMaxSyscallInterruptPriority
; -----------------------------------------------------------
.align 4
ulPortGetIPSR: .asmfunc
mrs r0, ipsr
bx r14
.endasmfunc
; -----------------------------------------------------------
.align 4
vPortSetInterruptMask: .asmfunc
push {r0}
ldr r0, ulMaxSyscallInterruptPriorityConst
msr basepri, r0
pop {r0}
bx r14
.endasmfunc
; -----------------------------------------------------------
.align 4
xPortPendSVHandler: .asmfunc
mrs r0, psp
isb
;/* Get the location of the current TCB. */
ldr r3, pxCurrentTCBConst
ldr r2, [r3]
;/* Save the core registers. */
stmdb r0!, {r4-r11}
;/* Save the new top of stack into the first member of the TCB. */
str r0, [r2]
stmdb sp!, {r3, r14}
ldr r0, ulMaxSyscallInterruptPriorityConst
ldr r1, [r0]
msr basepri, r1
dsb
isb
bl vTaskSwitchContext
mov r0, #0
msr basepri, r0
ldmia sp!, {r3, r14}
;/* The first item in pxCurrentTCB is the task top of stack. */
ldr r1, [r3]
ldr r0, [r1]
;/* Pop the core registers. */
ldmia r0!, {r4-r11}
msr psp, r0
isb
bx r14
.endasmfunc
; -----------------------------------------------------------
.align 4
vPortSVCHandler: .asmfunc
;/* Get the location of the current TCB. */
ldr r3, pxCurrentTCBConst
ldr r1, [r3]
ldr r0, [r1]
;/* Pop the core registers. */
ldmia r0!, {r4-r11}
msr psp, r0
isb
mov r0, #0
msr basepri, r0
orr r14, #0xd
bx r14
.endasmfunc
; -----------------------------------------------------------
.align 4
vPortStartFirstTask: .asmfunc
;/* Use the NVIC offset register to locate the stack. */
ldr r0, NVICOffsetConst
ldr r0, [r0]
ldr r0, [r0]
;/* Set the msp back to the start of the stack. */
msr msp, r0
;/* Clear the bit that indicates the FPU is in use in case the FPU was used
;before the scheduler was started - which would otherwise result in the
;unnecessary leaving of space in the SVC stack for lazy saving of FPU
;registers. */
mov r0, #0
msr control, r0
;/* Call SVC to start the first task. */
cpsie i
cpsie f
dsb
isb
svc #0
.endasmfunc
; -----------------------------------------------------------
|
