| ;/* |
| ; * 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 |
| ; * |
| ; */ |
| |
| IMPORT ulCriticalNesting ; |
| IMPORT pxCurrentTCB ; |
| |
| |
| MACRO |
| portRESTORE_CONTEXT |
| |
| |
| LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was... |
| LDR R0, [R0] ; ... stored in pxCurrentTCB |
| LDR LR, [R0] |
| |
| LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on... |
| LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var. |
| STR R1, [R0] ; |
| |
| LDMFD LR!, {R0} ; Get the SPSR from the stack. |
| MSR SPSR_cxsf, R0 ; |
| |
| LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task. |
| NOP ; |
| |
| LDR LR, [LR, #+60] ; Restore the return address |
| |
| ; And return - correcting the offset in the LR to obtain ... |
| SUBS PC, LR, #4 ; ...the correct address. |
| |
| MEND |
| |
| ; /**********************************************************************/ |
| |
| MACRO |
| portSAVE_CONTEXT |
| |
| |
| STMDB SP!, {R0} ; Store R0 first as we need to use it. |
| |
| STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer. |
| NOP ; |
| SUB SP, SP, #4 ; |
| LDMIA SP!,{R0} ; |
| |
| STMDB R0!, {LR} ; Push the return address onto the stack. |
| MOV LR, R0 ; Now we have saved LR we can use it instead of R0. |
| LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack. |
| |
| STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack. |
| NOP ; |
| SUB LR, LR, #60 ; |
| |
| MRS R0, SPSR ; Push the SPSR onto the task stack. |
| STMDB LR!, {R0} ; |
| |
| LDR R0, =ulCriticalNesting ; |
| LDR R0, [R0] ; |
| STMDB LR!, {R0} ; |
| |
| LDR R0, =pxCurrentTCB ; Store the new top of stack for the task. |
| LDR R1, [R0] ; |
| STR LR, [R1] ; |
| |
| MEND |
| |
| END |