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    ***************************************************************************
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    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
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    ***************************************************************************
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*/

#include "FreeRTOS.h"
#include "task.h"

/*
 * Two test tasks that fill the CPU registers with known values before
 * continuously looping round checking that each register still contains its
 * expected value.  Both tasks use a separate set of values, with an incorrect
 * value being found at any time being indicative of an error in the context
 * switch mechanism.  One of the tasks uses a yield instruction to increase the
 * test coverage.  The nature of these tasks necessitates that they are written
 * in assembly code.
 */
static void vRegTest1( void *pvParameters );
static void vRegTest2( void *pvParameters );

/*
 * A task that tests the management of the Interrupt Controller (IC) during a
 * context switch.  The state of the IC current mask level must be maintained
 * across context switches.  Also, yields must be able to be performed when the
 * interrupt controller mask is not zero.  This task tests both these
 * requirements.
 */
static void prvICCheck1Task( void *pvParameters );

/* Counters used to ensure the tasks are still running. */
static volatile unsigned long ulRegTest1Counter = 0UL, ulRegTest2Counter = 0UL, ulICTestCounter = 0UL;

/* Handle to the task that checks the interrupt controller behaviour.  This is
used by the traceTASK_SWITCHED_OUT() macro, which is defined in
FreeRTOSConfig.h and can be removed - it is just for the purpose of this test. */
xTaskHandle xICTestTask = NULL;

/* Variable that gets set to pdTRUE by traceTASK_SWITCHED_OUT each time
is switched out. */
volatile unsigned long ulTaskSwitchedOut;
/*-----------------------------------------------------------*/

void vStartRegTestTasks( void )
{
	xTaskCreate( vRegTest1, ( signed char * ) "RTest1", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
	xTaskCreate( vRegTest2, ( signed char * ) "RTest1", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, NULL );
	xTaskCreate( prvICCheck1Task, ( signed char * ) "ICCheck", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY, &xICTestTask );
}
/*-----------------------------------------------------------*/

static void vRegTest1( void *pvParameters )
{
	__asm volatile
	(
		"	mov		r2, #0x02							\n" /* Fill the registers with known values, r0 is always 0 and r1 is the stack pointer. */
		"	mov		r3, #0x03							\n"
		"	mov		r4, #0x04							\n"
		"	mov		r5, #0x05							\n"
		"	mov		r6, #0x06							\n"
		"	mov		r7, #0x07							\n"
		"	mov		r8, #0x08							\n"
		"	mov		r9, #0x09							\n"
		"	mov		r10, #0x0a							\n"
		"	mov		r11, #0x0b							\n"
		"	mov		r12, #0x0c							\n"
		"	mov		r13, #0x0d							\n"
		"	mov		r14, #0x0e							\n"
		"	mov		r15, #0x0f							\n"
		"												\n"
		"reg_check_loop_1:								\n"
		"	trap	#31									\n"
		"	cmp		r2, #0x02							\n" /* Check that each register still contains the expected value, jump to an infinite loop if an error is found. */
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r3, #0x03							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r4, #0x04							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r5, #0x05							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r6, #0x06							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r7, #0x07							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r8, #0x08							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r9, #0x09							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r10, #0x0a							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r11, #0x0b							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r12, #0x0c							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r13, #0x0d							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r14, #0x0e							\n"
		"	bne.s	reg_check_error_1					\n"
		"	cmp		r15, #0x0f							\n"
		"	bne.s	reg_check_error_1					\n"
		"												\n"
		"	ld		r2, [r0]+short(ulRegTest1Counter)	\n" /* Increment the loop counter to show that this task is still running error free. */
		"	add		r2, #1								\n"
		"	st		r2, [r0]+short(ulRegTest1Counter)	\n"
		"	mov		r2, #0x02							\n"
		"												\n"
		"	bra.s	reg_check_loop_1					\n" /* Do it all again. */
		"												\n"
		"reg_check_error_1:								\n"
			"bra.s		.								\n"
	);
}
/*-----------------------------------------------------------*/

static void vRegTest2( void *pvParameters )
{
	__asm volatile
	(
		"	mov		r2, #0x12							\n" /* Fill the registers with known values, r0 is always 0 and r1 is the stack pointer. */
		"	mov		r3, #0x13							\n"
		"	mov		r4, #0x14							\n"
		"	mov		r5, #0x15							\n"
		"	mov		r6, #0x16							\n"
		"	mov		r7, #0x17							\n"
		"	mov		r8, #0x18							\n"
		"	mov		r9, #0x19							\n"
		"	mov		r10, #0x1a							\n"
		"	mov		r11, #0x1b							\n"
		"	mov		r12, #0x1c							\n"
		"	mov		r13, #0x1d							\n"
		"	mov		r14, #0x1e							\n"
		"	mov		r15, #0x1f							\n"
		"												\n"
		"reg_check_loop_2:								\n"
		"	cmp		r2, #0x12							\n" /* Check that each register still contains the expected value, jump to an infinite loop if an error is found. */
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r3, #0x13							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r4, #0x14							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r5, #0x15							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r6, #0x16							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r7, #0x17							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r8, #0x18							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r9, #0x19							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r10, #0x1a							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r11, #0x1b							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r12, #0x1c							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r13, #0x1d							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r14, #0x1e							\n"
		"	bne.s	reg_check_error_2					\n"
		"	cmp		r15, #0x1f							\n"
		"	bne.s	reg_check_error_2					\n"
		"												\n"
		"	ld		r2, [r0]+short(ulRegTest2Counter)	\n" /* Increment the loop counter to show that this task is still running error free. */
		"	add		r2, #1								\n"
		"	st		r2, [r0]+short(ulRegTest2Counter)	\n"
		"	mov		r2, #0x12							\n"
		"												\n"
		"	bra.s	reg_check_loop_2					\n" /* Do it all again. */
		"												\n"
		"reg_check_error_2:								\n"
			"bra.s		.								\n"
	);
}
/*-----------------------------------------------------------*/

static void prvICCheck1Task( void *pvParameters )
{
long lICCheckStatus = pdPASS;

	for( ;; )
	{
		/* At this point the interrupt mask should be zero. */
		if( ic->cpl != 0 )
		{
			lICCheckStatus = pdFAIL;
		}

		/* If we yield here, it should still be 0 when the task next runs.
		ulTaskSwitchedOut is just used to check that a switch does actually
		happen. */
		ulTaskSwitchedOut = pdFALSE;
		taskYIELD();
		if( ( ulTaskSwitchedOut != pdTRUE ) || ( ic->cpl != 0 ) )
		{
			lICCheckStatus = pdFAIL;
		}

		/* Set the interrupt mask to portSYSTEM_INTERRUPT_PRIORITY_LEVEL + 1,
		before checking it is as expected. */
		taskENTER_CRITICAL();
		if( ic->cpl != ( portSYSTEM_INTERRUPT_PRIORITY_LEVEL + 1 ) )
		{
			lICCheckStatus = pdFAIL;
		}

		/* If we yield here, it should still be
		portSYSTEM_INTERRUPT_PRIORITY_LEVEL + 10 when the task next runs.  */
		ulTaskSwitchedOut = pdFALSE;
		taskYIELD();
		if( ( ulTaskSwitchedOut != pdTRUE ) || ( ic->cpl != ( portSYSTEM_INTERRUPT_PRIORITY_LEVEL + 1 ) ) )
		{
			lICCheckStatus = pdFAIL;
		}

		/* Return the interrupt mask to its default state. */
		taskEXIT_CRITICAL();

		/* Just increment a loop counter so the check task knows if this task
		is still running or not. */
		if( lICCheckStatus == pdPASS )
		{
			ulICTestCounter++;
		}
	}
}
/*-----------------------------------------------------------*/

portBASE_TYPE xAreRegTestTasksStillRunning( void )
{
static unsigned long ulLastCounter1 = 0UL, ulLastCounter2 = 0UL, ulLastICTestCounter = 0UL;
long lReturn;

	/* Check that both loop counters are still incrementing, indicating that
	both reg test tasks are still running error free. */
	if( ulLastCounter1 == ulRegTest1Counter )
	{
		lReturn = pdFAIL;
	}
	else if( ulLastCounter2 == ulRegTest2Counter )
	{
		lReturn = pdFAIL;
	}
	else if( ulLastICTestCounter == ulICTestCounter )
	{
		lReturn = pdFAIL;
	}
	else
	{
		lReturn = pdPASS;
	}

	ulLastCounter1 = ulRegTest1Counter;
	ulLastCounter2 = ulRegTest2Counter;
	ulLastICTestCounter = ulICTestCounter;

	return lReturn;
}