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/*
FreeRTOS V9.0.0rc1 - Copyright (C) 2016 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
.extern vTaskSwitchContext
.set noat
# Exported to start the first task.
.globl restore_sp_from_pxCurrentTCB
# Entry point for exceptions.
.section .exceptions.entry, "xa"
# Save the entire context of a task.
save_context:
addi ea, ea, -4 # Point to the next instruction.
addi sp, sp, -116 # Create space on the stack.
stw ra, 0(sp)
# Leave a gap for muldiv 0
stw at, 8(sp)
stw r2, 12(sp)
stw r3, 16(sp)
stw r4, 20(sp)
stw r5, 24(sp)
stw r6, 28(sp)
stw r7, 32(sp)
stw r8, 36(sp)
stw r9, 40(sp)
stw r10, 44(sp)
stw r11, 48(sp)
stw r12, 52(sp)
stw r13, 56(sp)
stw r14, 60(sp)
stw r15, 64(sp)
rdctl r5, estatus # Save the eStatus
stw r5, 68(sp)
stw ea, 72(sp) # Save the PC
stw r16, 76(sp) # Save the remaining registers
stw r17, 80(sp)
stw r18, 84(sp)
stw r19, 88(sp)
stw r20, 92(sp)
stw r21, 96(sp)
stw r22, 100(sp)
stw r23, 104(sp)
stw gp, 108(sp)
stw fp, 112(sp)
save_sp_to_pxCurrentTCB:
movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer
ldw et, (et) # Load the value of the pxCurrentTCB pointer
stw sp, (et) # Store the stack pointer into the top of the TCB
.section .exceptions.irqtest, "xa"
hw_irq_test:
/*
* Test to see if the exception was a software exception or caused
* by an external interrupt, and vector accordingly.
*/
rdctl r4, ipending # Load the Pending Interrupts indication
rdctl r5, estatus # Load the eStatus (enabled interrupts).
andi r2, r5, 1 # Are interrupts enabled globally.
beq r2, zero, soft_exceptions # Interrupts are not enabled.
beq r4, zero, soft_exceptions # There are no interrupts triggered.
.section .exceptions.irqhandler, "xa"
hw_irq_handler:
call alt_irq_handler # Call the alt_irq_handler to deliver to the registered interrupt handler.
.section .exceptions.irqreturn, "xa"
restore_sp_from_pxCurrentTCB:
movia et, pxCurrentTCB # Load the address of the pxCurrentTCB pointer
ldw et, (et) # Load the value of the pxCurrentTCB pointer
ldw sp, (et) # Load the stack pointer with the top value of the TCB
restore_context:
ldw ra, 0(sp) # Restore the registers.
# Leave a gap for muldiv 0.
ldw at, 8(sp)
ldw r2, 12(sp)
ldw r3, 16(sp)
ldw r4, 20(sp)
ldw r5, 24(sp)
ldw r6, 28(sp)
ldw r7, 32(sp)
ldw r8, 36(sp)
ldw r9, 40(sp)
ldw r10, 44(sp)
ldw r11, 48(sp)
ldw r12, 52(sp)
ldw r13, 56(sp)
ldw r14, 60(sp)
ldw r15, 64(sp)
ldw et, 68(sp) # Load the eStatus
wrctl estatus, et # Write the eStatus
ldw ea, 72(sp) # Load the Program Counter
ldw r16, 76(sp)
ldw r17, 80(sp)
ldw r18, 84(sp)
ldw r19, 88(sp)
ldw r20, 92(sp)
ldw r21, 96(sp)
ldw r22, 100(sp)
ldw r23, 104(sp)
ldw gp, 108(sp)
ldw fp, 112(sp)
addi sp, sp, 116 # Release stack space
eret # Return to address ea, loading eStatus into Status.
.section .exceptions.soft, "xa"
soft_exceptions:
ldw et, 0(ea) # Load the instruction where the interrupt occured.
movhi at, %hi(0x003B683A) # Load the registers with the trap instruction code
ori at, at, %lo(0x003B683A)
cmpne et, et, at # Compare the trap instruction code to the last excuted instruction
beq et, r0, call_scheduler # its a trap so switchcontext
break # This is an un-implemented instruction or muldiv problem.
br restore_context # its something else
call_scheduler:
addi ea, ea, 4 # A trap was called, increment the program counter so it is not called again.
stw ea, 72(sp) # Save the new program counter to the context.
call vTaskSwitchContext # Pick the next context.
br restore_sp_from_pxCurrentTCB # Switch in the task context and restore.
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