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- /*
- * FreeRTOS Kernel V10.4.6
- * 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
- *
- */
- EXTERN pxCurrentTCB
- EXTERN ulCriticalNesting
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- ; Context save and restore macro definitions
- ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
- portSAVE_CONTEXT MACRO
- ; Push R0 as we are going to use the register.
- STMDB SP!, {R0}
- ; Set R0 to point to the task stack pointer.
- STMDB SP, {SP}^
- NOP
- SUB SP, SP, #4
- LDMIA SP!, {R0}
- ; Push the return address onto the stack.
- STMDB R0!, {LR}
- ; Now we have saved LR we can use it instead of R0.
- MOV LR, R0
- ; Pop R0 so we can save it onto the system mode stack.
- LDMIA SP!, {R0}
- ; Push all the system mode registers onto the task stack.
- STMDB LR, {R0-LR}^
- NOP
- SUB LR, LR, #60
- ; Push the SPSR onto the task stack.
- MRS R0, SPSR
- STMDB LR!, {R0}
- LDR R0, =ulCriticalNesting
- LDR R0, [R0]
- STMDB LR!, {R0}
- ; Store the new top of stack for the task.
- LDR R1, =pxCurrentTCB
- LDR R0, [R1]
- STR LR, [R0]
- ENDM
- portRESTORE_CONTEXT MACRO
- ; Set the LR to the task stack.
- LDR R1, =pxCurrentTCB
- LDR R0, [R1]
- LDR LR, [R0]
- ; The critical nesting depth is the first item on the stack.
- ; Load it into the ulCriticalNesting variable.
- LDR R0, =ulCriticalNesting
- LDMFD LR!, {R1}
- STR R1, [R0]
- ; Get the SPSR from the stack.
- LDMFD LR!, {R0}
- MSR SPSR_cxsf, R0
- ; Restore all system mode registers for the task.
- LDMFD LR, {R0-R14}^
- NOP
- ; Restore the return address.
- LDR LR, [LR, #+60]
- ; And return - correcting the offset in the LR to obtain the
- ; correct address.
- SUBS PC, LR, #4
- ENDM
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