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portASM.s
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portASM.s
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;/*
; FreeRTOS V8.2.1 - Copyright (C) 2015 Real Time Engineers Ltd.
; All rights reserved
;
;
; ***************************************************************************
; * *
; * FreeRTOS tutorial books are available in pdf and paperback. *
; * Complete, revised, and edited pdf reference manuals are also *
; * available. *
; * *
; * Purchasing FreeRTOS documentation will not only help you, by *
; * ensuring you get running as quickly as possible and with an *
; * in-depth knowledge of how to use FreeRTOS, it will also help *
; * the FreeRTOS project to continue with its mission of providing *
; * professional grade, cross platform, de facto standard solutions *
; * for microcontrollers - completely free of charge! *
; * *
; * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
; * *
; * Thank you for using FreeRTOS, and thank you for your support! *
; * *
; ***************************************************************************
;
;
; This file is part of the FreeRTOS distribution.
;
; FreeRTOS is free software; you can redistribute it and/or modify it under
; the terms of the GNU General Public License (version 2) as published by the
; Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
; >>>NOTE<<< The modification to the GPL is included to allow you to
; distribute a combined work that includes FreeRTOS without being obliged to
; provide the source code for proprietary components outside of the FreeRTOS
; kernel. FreeRTOS is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
; more details. You should have received a copy of the GNU General Public
; License and the FreeRTOS license exception along with FreeRTOS; if not it
; can be viewed here: http://www.freertos.org/a00114.html and also obtained
; by writing to Richard Barry, contact details for whom are available on the
; FreeRTOS WEB site.
;
; 1 tab == 4 spaces!
;
; http://www.FreeRTOS.org - Documentation, latest information, license and
; contact details.
;
; http://www.SafeRTOS.com - A version that is certified for use in safety
; critical systems.
;
; http://www.OpenRTOS.com - Commercial support, development, porting,
; licensing and training services.
;*/
INCLUDE portmacro.inc
INCLUDE address.inc
IMPORT vApplicationIRQHandler
IMPORT vTaskSwitchContext
IMPORT ulPortYieldRequired
IMPORT ulPortInterruptNesting
IMPORT vTaskSwitchContext
EXPORT FreeRTOS_SWI_Handler
EXPORT FreeRTOS_IRQ_Handler
EXPORT vPortRestoreTaskContext
ARM
AREA PORT_ASM, CODE, READONLY
PRESERVE8
portICCPMR_PRIORITY_MASK_OFFSET EQU ( 0x04 )
portICCIAR_INTERRUPT_ACKNOWLEDGE_OFFSET EQU ( 0x0C )
portICCEOIR_END_OF_INTERRUPT_OFFSET EQU ( 0x10 )
portICCBPR_BINARY_POINT_OFFSET EQU ( 0x08 )
portICCRPR_RUNNING_PRIORITY_OFFSET EQU ( 0x14 )
configINTERRUPT_CONTROLLER_BASE_ADDRESS EQU ( 0x10040000 )
portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS EQU ( configINTERRUPT_CONTROLLER_BASE_ADDRESS )
portICCPMR_PRIORITY_MASK_REGISTER EQU ( ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCPMR_PRIORITY_MASK_OFFSET ) )
portICCIAR_INTERRUPT_ACKNOWLEDGE_REGISTER_ADDRESS EQU ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCIAR_INTERRUPT_ACKNOWLEDGE_OFFSET )
portICCEOIR_END_OF_INTERRUPT_REGISTER_ADDRESS EQU ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCEOIR_END_OF_INTERRUPT_OFFSET )
portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS EQU ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCPMR_PRIORITY_MASK_OFFSET )
portICCBPR_BINARY_POINT_REGISTER EQU ( ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCBPR_BINARY_POINT_OFFSET ) )
portICCRPR_RUNNING_PRIORITY_REGISTER EQU ( ( portINTERRUPT_CONTROLLER_CPU_INTERFACE_ADDRESS + portICCRPR_RUNNING_PRIORITY_OFFSET ) )
ulICCIAR EQU ( ( ( portICCIAR_INTERRUPT_ACKNOWLEDGE_REGISTER_ADDRESS ) ) )
ulICCEOIR EQU ( ( ( portICCEOIR_END_OF_INTERRUPT_REGISTER_ADDRESS ) ) )
ulICCPMR EQU ( ( ( portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS ) ) )
; ( ( ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) ) )
ulAsmAPIPriorityMask EQU 200
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; SVC handler is used to yield a task.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
FreeRTOS_SWI_Handler
PRESERVE8
; Save the context of the current task and select a new task to run.
portSAVE_CONTEXT
LDR R0, =vTaskSwitchContext
BLX R0
portRESTORE_CONTEXT
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; vPortRestoreTaskContext is used to start the scheduler.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
vPortRestoreTaskContext
; Switch to system mode
CPS #SYS_MODE
portRESTORE_CONTEXT
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; PL390 GIC interrupt handler
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
FreeRTOS_IRQ_Handler
; Return to the interrupted instruction.
SUB lr, lr, #4
; Push the return address and SPSR
PUSH {lr}
MRS lr, SPSR
PUSH {lr}
; Change to supervisor mode to allow reentry.
CPS #SVC_MODE
; Push used registers.
PUSH {r0-r4, r12}
; Increment nesting count. r3 holds the address of ulPortInterruptNesting
; for future use. r1 holds the original ulPortInterruptNesting value for
; future use.
LDR r3, =ulPortInterruptNesting
LDR r1, [r3]
ADD r4, r1, #1
STR r4, [r3]
; Read value from the interrupt acknowledge register, which is stored in r0
; for future parameter and interrupt clearing use.
LDR r2, =ulICCIAR
LDR r0, [r2]
; Ensure bit 2 of the stack pointer is clear. r2 holds the bit 2 value for
; future use.
MOV r2, sp
AND r2, r2, #4
SUB sp, sp, r2
; Call the interrupt handler
PUSH {r0-r3, lr}
LDR r1, =vApplicationIRQHandler
BLX r1
POP {r0-r3, lr}
ADD sp, sp, r2
CPSID i
; Write the value read from ICCIAR to ICCEOIR
LDR r4, =ulICCEOIR
STR r0, [r4]
; Restore the old nesting count
STR r1, [r3]
; A context switch is never performed if the nesting count is not 0
CMP r1, #0
BNE exit_without_switch
; Did the interrupt request a context switch? r1 holds the address of
; ulPortYieldRequired and r0 the value of ulPortYieldRequired for future
; use.
LDR r1, =ulPortYieldRequired
LDR r0, [r1]
CMP r0, #0
BNE switch_before_exit
exit_without_switch
; No context switch. Restore used registers, LR_irq and SPSR before
; returning.
POP {r0-r4, r12}
CPS #IRQ_MODE
POP {LR}
MSR SPSR_cxsf, LR
POP {LR}
MOVS PC, LR
switch_before_exit
; A context swtich is to be performed. Clear the context switch pending
; flag.
MOV r0, #0
STR r0, [r1]
; Restore used registers, LR-irq and SPSR before saving the context
; to the task stack.
POP {r0-r4, r12}
CPS #IRQ_MODE
POP {LR}
MSR SPSR_cxsf, LR
POP {LR}
portSAVE_CONTEXT
; Call the function that selects the new task to execute.
; vTaskSwitchContext() if vTaskSwitchContext() uses LDRD or STRD
; instructions, or 8 byte aligned stack allocated data. LR does not need
; saving as a new LR will be loaded by portRESTORE_CONTEXT anyway.
LDR r0, =vTaskSwitchContext
BLX r0
; Restore the context of, and branch to, the task selected to execute next.
portRESTORE_CONTEXT
END