mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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145 lines
5 KiB
C
145 lines
5 KiB
C
;/*
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; FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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;
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;
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; ***************************************************************************
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; * *
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; * FreeRTOS tutorial books are available in pdf and paperback. *
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; * Complete, revised, and edited pdf reference manuals are also *
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; * available. *
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; * *
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; * Purchasing FreeRTOS documentation will not only help you, by *
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; * ensuring you get running as quickly as possible and with an *
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; * in-depth knowledge of how to use FreeRTOS, it will also help *
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; * the FreeRTOS project to continue with its mission of providing *
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; * professional grade, cross platform, de facto standard solutions *
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; * for microcontrollers - completely free of charge! *
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; * *
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; * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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; * *
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; * Thank you for using FreeRTOS, and thank you for your support! *
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; * *
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; ***************************************************************************
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;
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;
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; This file is part of the FreeRTOS distribution.
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;
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; FreeRTOS is free software; you can redistribute it and/or modify it under
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; the terms of the GNU General Public License (version 2) as published by the
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; Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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; >>>NOTE<<< The modification to the GPL is included to allow you to
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; distribute a combined work that includes FreeRTOS without being obliged to
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; provide the source code for proprietary components outside of the FreeRTOS
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; kernel. FreeRTOS is distributed in the hope that it will be useful, but
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; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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; more details. You should have received a copy of the GNU General Public
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; License and the FreeRTOS license exception along with FreeRTOS; if not it
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; can be viewed here: http://www.freertos.org/a00114.html and also obtained
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; by writing to Richard Barry, contact details for whom are available on the
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; FreeRTOS WEB site.
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;
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; 1 tab == 4 spaces!
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;
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; http://www.FreeRTOS.org - Documentation, latest information, license and
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; contact details.
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;
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; http://www.SafeRTOS.com - A version that is certified for use in safety
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; critical systems.
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;
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; http://www.OpenRTOS.com - Commercial support, development, porting,
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; licensing and training services.
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;*/
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EXTERN vTaskSwitchContext
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EXTERN ulCriticalNesting
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EXTERN pxCurrentTCB
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EXTERN ulPortTaskHasFPUContext
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EXTERN ulAsmAPIPriorityMask
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portSAVE_CONTEXT macro
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; Save the LR and SPSR onto the system mode stack before switching to
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; system mode to save the remaining system mode registers
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SRSDB sp!, #SYS_MODE
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CPS #SYS_MODE
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PUSH {R0-R12, R14}
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; Push the critical nesting count
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LDR R2, =ulCriticalNesting
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LDR R1, [R2]
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PUSH {R1}
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; Does the task have a floating point context that needs saving? If
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; ulPortTaskHasFPUContext is 0 then no.
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LDR R2, =ulPortTaskHasFPUContext
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LDR R3, [R2]
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CMP R3, #0
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; Save the floating point context, if any
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FMRXNE R1, FPSCR
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VPUSHNE {D0-D15}
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VPUSHNE {D16-D31}
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PUSHNE {R1}
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; Save ulPortTaskHasFPUContext itself
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PUSH {R3}
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; Save the stack pointer in the TCB
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LDR R0, =pxCurrentTCB
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LDR R1, [R0]
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STR SP, [R1]
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endm
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; /**********************************************************************/
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portRESTORE_CONTEXT macro
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; Switch to system mode
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CPS #SYS_MODE
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; Set the SP to point to the stack of the task being restored.
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LDR R0, =pxCurrentTCB
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LDR R1, [R0]
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LDR SP, [R1]
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; Is there a floating point context to restore? If the restored
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; ulPortTaskHasFPUContext is zero then no.
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LDR R0, =ulPortTaskHasFPUContext
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POP {R1}
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STR R1, [R0]
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CMP R1, #0
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; Restore the floating point context, if any
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LDMFDNE SP!, {R0}
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VPOPNE {D16-D31}
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VPOPNE {D0-D15}
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VMSRNE FPSCR, R0
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; Restore the critical section nesting depth
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LDR R0, =ulCriticalNesting
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POP {R1}
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STR R1, [R0]
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; Ensure the priority mask is correct for the critical nesting depth
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LDR R2, =portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS
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CMP R1, #0
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MOVEQ R4, #255
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LDRNE R4, =( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT )
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STR R4, [r2]
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; Restore all system mode registers other than the SP (which is already
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; being used)
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POP {R0-R12, R14}
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; Return to the task code, loading CPSR on the way.
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RFEIA sp!
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endm
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