; /* | |
* ; * FreeRTOS Kernel V10.3.1 | |
* ; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
* ; * | |
* ; * 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. | |
* ; * | |
* ; * http://www.FreeRTOS.org | |
* ; * http://aws.amazon.com/freertos | |
* ; * | |
* ; * 1 tab == 4 spaces! | |
* ; */ | |
EXTERN vTaskSwitchContext | |
EXTERN ulCriticalNesting | |
EXTERN pxCurrentTCB | |
EXTERN ulPortTaskHasFPUContext | |
EXTERN ulAsmAPIPriorityMask | |
portSAVE_CONTEXT macro | |
; | |
Save the LR and SPSR onto the system mode stack before switching to | |
; | |
system mode to save the remaining system mode registers | |
SRSDB sp !, # SYS_MODE | |
CPS # SYS_MODE | |
PUSH { R0 - R12, R14 } | |
; | |
Push the critical nesting count | |
LDR R2, = ulCriticalNesting | |
LDR R1, [ R2 ] | |
PUSH { R1 } | |
; | |
Does the task have a floating point context that needs saving ? If | |
; | |
ulPortTaskHasFPUContext is 0 then no. | |
LDR R2, = ulPortTaskHasFPUContext | |
LDR R3, [ R2 ] | |
CMP R3, # 0 | |
; | |
Save the floating point context, if any | |
FMRXNE R1, FPSCR | |
VPUSHNE { D0 - D15 } | |
VPUSHNE { D16 - D31 } | |
PUSHNE { R1 } | |
; | |
Save ulPortTaskHasFPUContext itself | |
PUSH { R3 } | |
; | |
Save the stack pointer in the TCB | |
LDR R0, = pxCurrentTCB | |
LDR R1, [ R0 ] | |
STR SP, [ R1 ] | |
endm | |
; /**********************************************************************/ | |
portRESTORE_CONTEXT macro | |
; | |
Set the SP to point to the stack of the task being restored. | |
LDR R0, = pxCurrentTCB | |
LDR R1, [ R0 ] | |
LDR SP, [ R1 ] | |
; | |
Is there a floating point context to restore ? If the restored | |
; | |
ulPortTaskHasFPUContext is zero then no. | |
LDR R0, = ulPortTaskHasFPUContext | |
POP { R1 } | |
STR R1, [ R0 ] | |
CMP R1, # 0 | |
; | |
Restore the floating point context, if any | |
POPNE { R0 } | |
VPOPNE { D16 - D31 } | |
VPOPNE { D0 - D15 } | |
VMSRNE FPSCR, R0 | |
; | |
Restore the critical section nesting depth | |
LDR R0, = ulCriticalNesting | |
POP { R1 } | |
STR R1, [ R0 ] | |
; | |
Ensure the priority mask is correct for the critical nesting depth | |
LDR R2, = portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS | |
CMP R1, # 0 | |
MOVEQ R4, # 255 | |
LDRNE R4, = ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) | |
STR R4, [ r2 ] | |
; | |
Restore all system mode registers other than the SP( which is already | |
; | |
being used ) | |
POP | |
{ | |
R0 - R12, R14 | |
} | |
Return to the task code, loading CPSR on the way. | |
RFEIA sp ! | |
endm |