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/*
FreeRTOS V8.2.0 - 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!
*/
/*-----------------------------------------------------------
* Components that can be compiled to either ARM or THUMB mode are
* contained in port.c The ISR routines, which can only be compiled
* to ARM mode, are contained in this file.
*----------------------------------------------------------*/
/*
*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
/* Constants required to handle critical sections. */
#define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
volatile uint32_t ulCriticalNesting = 9999UL;
/*-----------------------------------------------------------*/
/*
* The scheduler can only be started from ARM mode, hence the inclusion of this
* function here.
*/
void vPortISRStartFirstTask( void );
/*-----------------------------------------------------------*/
void vPortISRStartFirstTask( void )
{
/* Simply start the scheduler. This is included here as it can only be
called from ARM mode. */
asm volatile ( \
"LDR R0, =pxCurrentTCB \n\t" \
"LDR R0, [R0] \n\t" \
"LDR LR, [R0] \n\t" \
\
/* The critical nesting depth is the first item on the stack. */ \
/* Load it into the ulCriticalNesting variable. */ \
"LDR R0, =ulCriticalNesting \n\t" \
"LDMFD LR!, {R1} \n\t" \
"STR R1, [R0] \n\t" \
\
/* Get the SPSR from the stack. */ \
"LDMFD LR!, {R0} \n\t" \
"MSR SPSR, R0 \n\t" \
\
/* Restore all system mode registers for the task. */ \
"LDMFD LR, {R0-R14}^ \n\t" \
"NOP \n\t" \
\
/* Restore the return address. */ \
"LDR LR, [LR, #+60] \n\t" \
\
/* And return - correcting the offset in the LR to obtain the */ \
/* correct address. */ \
"SUBS PC, LR, #4 \n\t" \
);
}
/*-----------------------------------------------------------*/
void vPortTickISR( void )
{
/* Increment the RTOS tick count, then look for the highest priority
task that is ready to run. */
if( xTaskIncrementTick() != pdFALSE )
{
vTaskSwitchContext();
}
/* Ready for the next interrupt. */
TB_ClearITPendingBit( TB_IT_Update );
}
/*-----------------------------------------------------------*/
/*
* The interrupt management utilities can only be called from ARM mode. When
* THUMB_INTERWORK is defined the utilities are defined as functions here to
* ensure a switch to ARM mode. When THUMB_INTERWORK is not defined then
* the utilities are defined as macros in portmacro.h - as per other ports.
*/
#ifdef THUMB_INTERWORK
void vPortDisableInterruptsFromThumb( void ) __attribute__ ((naked));
void vPortEnableInterruptsFromThumb( void ) __attribute__ ((naked));
void vPortDisableInterruptsFromThumb( void )
{
asm volatile (
"STMDB SP!, {R0} \n\t" /* Push R0. */
"MRS R0, CPSR \n\t" /* Get CPSR. */
"ORR R0, R0, #0xC0 \n\t" /* Disable IRQ, FIQ. */
"MSR CPSR, R0 \n\t" /* Write back modified value. */
"LDMIA SP!, {R0} \n\t" /* Pop R0. */
"BX R14" ); /* Return back to thumb. */
}
void vPortEnableInterruptsFromThumb( void )
{
asm volatile (
"STMDB SP!, {R0} \n\t" /* Push R0. */
"MRS R0, CPSR \n\t" /* Get CPSR. */
"BIC R0, R0, #0xC0 \n\t" /* Enable IRQ, FIQ. */
"MSR CPSR, R0 \n\t" /* Write back modified value. */
"LDMIA SP!, {R0} \n\t" /* Pop R0. */
"BX R14" ); /* Return back to thumb. */
}
#endif /* THUMB_INTERWORK */
/*-----------------------------------------------------------*/
void vPortEnterCritical( void )
{
/* Disable interrupts as per portDISABLE_INTERRUPTS(); */
asm volatile (
"STMDB SP!, {R0} \n\t" /* Push R0. */
"MRS R0, CPSR \n\t" /* Get CPSR. */
"ORR R0, R0, #0xC0 \n\t" /* Disable IRQ, FIQ. */
"MSR CPSR, R0 \n\t" /* Write back modified value. */
"LDMIA SP!, {R0}" ); /* Pop R0. */
/* Now interrupts are disabled ulCriticalNesting can be accessed
directly. Increment ulCriticalNesting to keep a count of how many times
portENTER_CRITICAL() has been called. */
ulCriticalNesting++;
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
if( ulCriticalNesting > portNO_CRITICAL_NESTING )
{
/* Decrement the nesting count as we are leaving a critical section. */
ulCriticalNesting--;
/* If the nesting level has reached zero then interrupts should be
re-enabled. */
if( ulCriticalNesting == portNO_CRITICAL_NESTING )
{
/* Enable interrupts as per portEXIT_CRITICAL(). */
asm volatile (
"STMDB SP!, {R0} \n\t" /* Push R0. */
"MRS R0, CPSR \n\t" /* Get CPSR. */
"BIC R0, R0, #0xC0 \n\t" /* Enable IRQ, FIQ. */
"MSR CPSR, R0 \n\t" /* Write back modified value. */
"LDMIA SP!, {R0}" ); /* Pop R0. */
}
}
}
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