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/*
FreeRTOS V8.2.3 - Copyright (C) 2015 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!
*/
#include <xc.h>
#include <sys/asm.h>
#include "ISR_Support.h"
.set nomips16
.set noreorder
.extern pxCurrentTCB
.extern vTaskSwitchContext
.extern vPortIncrementTick
.extern xISRStackTop
.global vPortStartFirstTask
.global vPortYieldISR
.global vPortTickInterruptHandler
/******************************************************************/
.set noreorder
.set noat
.ent vPortTickInterruptHandler
vPortTickInterruptHandler:
portSAVE_CONTEXT
jal vPortIncrementTick
nop
portRESTORE_CONTEXT
.end vPortTickInterruptHandler
/******************************************************************/
.set noreorder
.set noat
.ent vPortStartFirstTask
vPortStartFirstTask:
/* Simply restore the context of the highest priority task that has been
created so far. */
portRESTORE_CONTEXT
.end vPortStartFirstTask
/*******************************************************************/
.set noreorder
.set noat
.ent vPortYieldISR
vPortYieldISR:
/* Make room for the context. First save the current status so it can be
manipulated. */
addiu sp, sp, -portCONTEXT_SIZE
mfc0 k1, _CP0_STATUS
/* Also save s6 and s5 so they can be used. Any nesting interrupts should
maintain the values of these registers across the ISR. */
sw s6, 44(sp)
sw s5, 40(sp)
sw k1, portSTATUS_STACK_LOCATION(sp)
/* Prepare to re-enabled interrupt above the kernel priority. */
ins k1, zero, 10, 6
ori k1, k1, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 10 )
ins k1, zero, 1, 4
/* s5 is used as the frame pointer. */
add s5, zero, sp
/* Swap to the system stack. This is not conditional on the nesting
count as this interrupt is always the lowest priority and therefore
the nesting is always 0. */
la sp, xISRStackTop
lw sp, (sp)
/* Set the nesting count. */
la k0, uxInterruptNesting
addiu s6, zero, 1
sw s6, 0(k0)
/* s6 holds the EPC value, this is saved with the rest of the context
after interrupts are enabled. */
mfc0 s6, _CP0_EPC
/* Re-enable interrupts above configMAX_SYSCALL_INTERRUPT_PRIORITY. */
mtc0 k1, _CP0_STATUS
/* Save the context into the space just created. s6 is saved again
here as it now contains the EPC value. */
sw ra, 120(s5)
sw s8, 116(s5)
sw t9, 112(s5)
sw t8, 108(s5)
sw t7, 104(s5)
sw t6, 100(s5)
sw t5, 96(s5)
sw t4, 92(s5)
sw t3, 88(s5)
sw t2, 84(s5)
sw t1, 80(s5)
sw t0, 76(s5)
sw a3, 72(s5)
sw a2, 68(s5)
sw a1, 64(s5)
sw a0, 60(s5)
sw v1, 56(s5)
sw v0, 52(s5)
sw s7, 48(s5)
sw s6, portEPC_STACK_LOCATION(s5)
/* s5 and s6 has already been saved. */
sw s4, 36(s5)
sw s3, 32(s5)
sw s2, 28(s5)
sw s1, 24(s5)
sw s0, 20(s5)
sw $1, 16(s5)
/* s7 is used as a scratch register as this should always be saved across
nesting interrupts. */
mfhi s7
sw s7, 12(s5)
mflo s7
sw s7, 8(s5)
/* Save the stack pointer to the task. */
la s7, pxCurrentTCB
lw s7, (s7)
sw s5, (s7)
/* Set the interrupt mask to the max priority that can use the API. The
yield handler will only be called at configKERNEL_INTERRUPT_PRIORITY which
is below configMAX_SYSCALL_INTERRUPT_PRIORITY - so this can only ever
raise the IPL value and never lower it. */
di
ehb
mfc0 s7, _CP0_STATUS
ins s7, zero, 10, 6
ori s6, s7, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 10 ) | 1
/* This mtc0 re-enables interrupts, but only above
configMAX_SYSCALL_INTERRUPT_PRIORITY. */
mtc0 s6, _CP0_STATUS
ehb
/* Clear the software interrupt in the core. */
mfc0 s6, _CP0_CAUSE
ins s6, zero, 8, 1
mtc0 s6, _CP0_CAUSE
ehb
/* Clear the interrupt in the interrupt controller. */
la s6, IFS0CLR
addiu s4, zero, 2
sw s4, (s6)
jal vTaskSwitchContext
nop
/* Clear the interrupt mask again. The saved status value is still in s7. */
mtc0 s7, _CP0_STATUS
ehb
/* Restore the stack pointer from the TCB. */
la s0, pxCurrentTCB
lw s0, (s0)
lw s5, (s0)
/* Restore the rest of the context. */
lw s0, 8(s5)
mtlo s0
lw s0, 12(s5)
mthi s0
lw $1, 16(s5)
lw s0, 20(s5)
lw s1, 24(s5)
lw s2, 28(s5)
lw s3, 32(s5)
lw s4, 36(s5)
/* s5 is loaded later. */
lw s6, 44(s5)
lw s7, 48(s5)
lw v0, 52(s5)
lw v1, 56(s5)
lw a0, 60(s5)
lw a1, 64(s5)
lw a2, 68(s5)
lw a3, 72(s5)
lw t0, 76(s5)
lw t1, 80(s5)
lw t2, 84(s5)
lw t3, 88(s5)
lw t4, 92(s5)
lw t5, 96(s5)
lw t6, 100(s5)
lw t7, 104(s5)
lw t8, 108(s5)
lw t9, 112(s5)
lw s8, 116(s5)
lw ra, 120(s5)
/* Protect access to the k registers, and others. */
di
ehb
/* Set nesting back to zero. As the lowest priority interrupt this
interrupt cannot have nested. */
la k0, uxInterruptNesting
sw zero, 0(k0)
/* Switch back to use the real stack pointer. */
add sp, zero, s5
/* Restore the real s5 value. */
lw s5, 40(sp)
/* Pop the status and epc values. */
lw k1, portSTATUS_STACK_LOCATION(sp)
lw k0, portEPC_STACK_LOCATION(sp)
/* Remove stack frame. */
addiu sp, sp, portCONTEXT_SIZE
mtc0 k1, _CP0_STATUS
mtc0 k0, _CP0_EPC
ehb
eret
nop
.end vPortYieldISR
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