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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
* ; *
* ; */
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
}
#if configFPU_D32 == 1
VPUSHNE {
D16 - D31
}
#endif; configFPU_D32
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
}
#if configFPU_D32 == 1
VPOPNE {
D16 - D31
}
#endif; configFPU_D32
VPOPNE {
D0 - D15
}
VMSRNE FPSCR, R0
;
Restore the critical section nesting depth
LDR R0, = ulCriticalNesting
POP {
R1
}
STR R1, [ R0 ]
;
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.CPSR has the interrupt
;
enable bit set appropriately
for the task about to execute.
RFEIA sp !
endm
|
