286 lines
10 KiB
C
286 lines
10 KiB
C
/*
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FreeRTOS V4.1.1 - Copyright (C) 2003-2006 Richard Barry.
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MCF5235 Port - Copyright (C) 2006 Christian Walter.
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License** as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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***************************************************************************
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* *
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* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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* *
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* This is a concise, step by step, 'hands on' guide that describes both *
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* general multitasking concepts and FreeRTOS specifics. It presents and *
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* explains numerous examples that are written using the FreeRTOS API. *
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* Full source code for all the examples is provided in an accompanying *
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* .zip file. *
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* *
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***************************************************************************
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***************************************************************************
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Please ensure to read the configuration and relevant port sections of the
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online documentation.
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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#include <stdlib.h>
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#include "FreeRTOS.h"
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#include "FreeRTOSConfig.h"
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#include "task.h"
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/* ------------------------ Types ----------------------------------------- */
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typedef volatile uint32_t vuint32;
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typedef volatile uint16_t vuint16;
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typedef volatile uint8_t vuint8;
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/* ------------------------ Defines --------------------------------------- */
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#define portVECTOR_TABLE __RAMVEC
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#define portVECTOR_SYSCALL ( 32 + portTRAP_YIELD )
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#define portVECTOR_TIMER ( 64 + 36 )
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#define MCF_PIT_PRESCALER 512UL
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#define MCF_PIT_TIMER_TICKS ( FSYS_2 / MCF_PIT_PRESCALER )
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#define MCF_PIT_MODULUS_REGISTER(freq) ( MCF_PIT_TIMER_TICKS / ( freq ) - 1UL)
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#define MCF_PIT_PMR0 ( *( vuint16 * )( void * )( &__IPSBAR[ 0x150002 ] ) )
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#define MCF_PIT_PCSR0 ( *( vuint16 * )( void * )( &__IPSBAR[ 0x150000 ] ) )
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#define MCF_PIT_PCSR_PRE(x) ( ( ( x ) & 0x000F ) << 8 )
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#define MCF_PIT_PCSR_EN ( 0x0001 )
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#define MCF_PIT_PCSR_RLD ( 0x0002 )
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#define MCF_PIT_PCSR_PIF ( 0x0004 )
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#define MCF_PIT_PCSR_PIE ( 0x0008 )
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#define MCF_PIT_PCSR_OVW ( 0x0010 )
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#define MCF_INTC0_ICR36 ( *( vuint8 * )( void * )( &__IPSBAR[ 0x000C64 ] ) )
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#define MCF_INTC0_IMRH ( *( vuint32 * )( void * )( &__IPSBAR[ 0x000C08 ] ) )
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#define MCF_INTC0_IMRH_INT_MASK36 ( 0x00000010 )
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#define MCF_INTC0_IMRH_MASKALL ( 0x00000001 )
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#define MCF_INTC0_ICRn_IP(x) ( ( ( x ) & 0x07 ) << 0 )
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#define MCF_INTC0_ICRn_IL(x) ( ( ( x ) & 0x07 ) << 3 )
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#define portNO_CRITICAL_NESTING ( ( uint32_t ) 0 )
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#define portINITIAL_CRITICAL_NESTING ( ( uint32_t ) 10 )
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/* ------------------------ Static variables ------------------------------ */
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volatile uint32_t ulCriticalNesting = portINITIAL_CRITICAL_NESTING;
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/* ------------------------ Static functions ------------------------------ */
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#if configUSE_PREEMPTION == 0
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static void prvPortPreemptiveTick ( void ) __attribute__ ((interrupt_handler));
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#else
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static void prvPortPreemptiveTick ( void );
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#endif
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/* ------------------------ Start implementation -------------------------- */
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StackType_t *
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pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode,
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void *pvParameters )
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{
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/* Place the parameter on the stack in the expected location. */
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*pxTopOfStack = ( StackType_t ) pvParameters;
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pxTopOfStack--;
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/* Place dummy return address on stack. Tasks should never terminate so
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* we can set this to anything. */
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*pxTopOfStack = ( StackType_t ) 0;
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pxTopOfStack--;
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/* Create a Motorola Coldfire exception stack frame. First comes the return
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* address. */
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*pxTopOfStack = ( StackType_t ) pxCode;
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pxTopOfStack--;
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/* Format, fault-status, vector number for exception stack frame. Task
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* run in supervisor mode. */
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*pxTopOfStack = 0x40002000UL | ( portVECTOR_SYSCALL + 32 ) << 18;
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pxTopOfStack--;
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/* Set the initial critical section nesting counter to zero. This value
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* is used to restore the value of ulCriticalNesting. */
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*pxTopOfStack = 0;
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*pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA6; /* A6 / FP */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA5; /* A5 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA4; /* A4 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA3; /* A3 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA2; /* A2 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA1; /* A1 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xA0; /* A0 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD7; /* D7 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD6; /* D6 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD5; /* D5 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD4; /* D4 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD3; /* D3 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD2; /* D2 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD1; /* D1 */
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pxTopOfStack--;
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*pxTopOfStack = ( StackType_t ) 0xD0; /* D0 */
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return pxTopOfStack;
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}
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/*
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* Called by portYIELD() or taskYIELD() to manually force a context switch.
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*/
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static void
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prvPortYield( void )
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{
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asm volatile ( "move.w #0x2700, %sr\n\t" );
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#if _GCC_USES_FP == 1
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asm volatile ( "unlk %fp\n\t" );
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#endif
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/* Perform the context switch. First save the context of the current task. */
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portSAVE_CONTEXT( );
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/* Find the highest priority task that is ready to run. */
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vTaskSwitchContext( );
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/* Restore the context of the new task. */
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portRESTORE_CONTEXT( );
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}
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#if configUSE_PREEMPTION == 0
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/*
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* The ISR used for the scheduler tick depends on whether the cooperative or
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* the preemptive scheduler is being used.
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*/
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static void
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prvPortPreemptiveTick ( void )
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{
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/* The cooperative scheduler requires a normal IRQ service routine to
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* simply increment the system tick.
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*/
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xTaskIncrementTick();
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MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIF;
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}
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#else
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static void
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prvPortPreemptiveTick( void )
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{
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asm volatile ( "move.w #0x2700, %sr\n\t" );
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#if _GCC_USES_FP == 1
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asm volatile ( "unlk %fp\n\t" );
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#endif
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portSAVE_CONTEXT( );
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MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIF;
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if( xTaskIncrementTick() != pdFALSE )
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{
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vTaskSwitchContext( );
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}
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portRESTORE_CONTEXT( );
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}
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#endif
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void
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vPortEnterCritical()
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{
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/* FIXME: We should store the old IPL here - How are we supposed to do
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* this.
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*/
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( void )portSET_IPL( portIPL_MAX );
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/* Now interrupts are disabled ulCriticalNesting can be accessed
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* directly. Increment ulCriticalNesting to keep a count of how many times
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* portENTER_CRITICAL() has been called. */
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ulCriticalNesting++;
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}
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void
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vPortExitCritical()
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{
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if( ulCriticalNesting > portNO_CRITICAL_NESTING )
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{
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/* Decrement the nesting count as we are leaving a critical section. */
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ulCriticalNesting--;
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/* If the nesting level has reached zero then interrupts should be
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re-enabled. */
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if( ulCriticalNesting == portNO_CRITICAL_NESTING )
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{
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( void )portSET_IPL( 0 );
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}
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}
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}
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BaseType_t
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xPortStartScheduler( void )
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{
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extern void ( *portVECTOR_TABLE[ ] ) ( );
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/* Add entry in vector table for yield system call. */
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portVECTOR_TABLE[ portVECTOR_SYSCALL ] = prvPortYield;
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/* Add entry in vector table for periodic timer. */
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portVECTOR_TABLE[ portVECTOR_TIMER ] = prvPortPreemptiveTick;
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/* Configure the timer for the system clock. */
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if ( configTICK_RATE_HZ > 0)
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{
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/* Configure prescaler */
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MCF_PIT_PCSR0 = MCF_PIT_PCSR_PRE( 0x9 ) | MCF_PIT_PCSR_RLD | MCF_PIT_PCSR_OVW;
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/* Initialize the periodic timer interrupt. */
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MCF_PIT_PMR0 = MCF_PIT_MODULUS_REGISTER( configTICK_RATE_HZ );
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/* Configure interrupt priority and level and unmask interrupt. */
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MCF_INTC0_ICR36 = MCF_INTC0_ICRn_IL( 0x1 ) | MCF_INTC0_ICRn_IP( 0x1 );
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MCF_INTC0_IMRH &= ~( MCF_INTC0_IMRH_INT_MASK36 | MCF_INTC0_IMRH_MASKALL );
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/* Enable interrupts */
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MCF_PIT_PCSR0 |= MCF_PIT_PCSR_PIE | MCF_PIT_PCSR_EN | MCF_PIT_PCSR_PIF;
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}
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/* Restore the context of the first task that is going to run. */
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portRESTORE_CONTEXT( );
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/* Should not get here. */
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return pdTRUE;
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}
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void
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vPortEndScheduler( void )
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{
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}
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