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/*

    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.

    ***************************************************************************

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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 exception 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.

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*/

/*

Changes from V3.2.1

        + CallReturn Depth increased from 8 to 10 levels to accomodate wizC/fedC V12.

Changes from V3.2.0

        + TBLPTRU is now initialised to zero during the initial stack creation of a new task. This solves

        an error on devices with more than 64kB ROM.

Changes from V3.0.0

        + ucCriticalNesting is now initialised to 0x7F to prevent interrupts from being

          handled before the scheduler is started.

Changes from V3.0.1

*/

/* Scheduler include files. */

#include <FreeRTOS.h>

#include <task.h>

#include <malloc.h>

/*---------------------------------------------------------------------------

 * Implementation of functions defined in portable.h for the WizC PIC18 port.

 *---------------------------------------------------------------------------*/

/*

 * We require the address of the pxCurrentTCB variable, but don't want to

 * know any details of its type.

 */

typedef void tskTCB;

extern volatile tskTCB * volatile pxCurrentTCB;

/*

 * Define minimal-stack constants

 * -----

 * FSR's:

 *              STATUS, WREG, BSR, PRODH, PRODL, FSR0H, FSR0L,

 *              FSR1H, FSR1L,TABLAT, (TBLPTRU), TBLPTRH, TBLPTRL,

 *              (PCLATU), PCLATH

 *              sfr's within parenthesis only on devices > 64kB

 * -----

 * Call/Return stack:

 *               2 bytes per entry on devices <= 64kB

 *               3 bytes per entry on devices >  64kB

 * -----

 * Other bytes:

 *               2 bytes: FunctionParameter for initial taskcode

 *               1 byte : Number of entries on call/return stack

 *               1 byte : ucCriticalNesting

 *              16 bytes: Free space on stack

 */

#if _ROMSIZE > 0x8000

        #define portSTACK_FSR_BYTES                             ( 15 )

        #define portSTACK_CALLRETURN_ENTRY_SIZE (  3 )

#else

        #define portSTACK_FSR_BYTES                             ( 13 )

        #define portSTACK_CALLRETURN_ENTRY_SIZE (  2 )

#endif

#define portSTACK_MINIMAL_CALLRETURN_DEPTH      ( 10 )

#define portSTACK_OTHER_BYTES                           ( 20 )

unsigned short usCalcMinStackSize               = 0;

/*-----------------------------------------------------------*/

/*

 * We initialise ucCriticalNesting to the middle value an

 * unsigned char can contain. This way portENTER_CRITICAL()

 * and portEXIT_CRITICAL() can be called without interrupts

 * being enabled before the scheduler starts.

 */

register unsigned char ucCriticalNesting = 0x7F;

/*-----------------------------------------------------------*/

/*

 * Initialise the stack of a new task.

 * See portSAVE_CONTEXT macro for description.

 */

portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )

{

unsigned char ucScratch;

        /*

         * Get the size of the RAMarea in page 0 used by the compiler

         * We do this here already to avoid W-register conflicts.

         */

        _Pragma("asm")

                movlw   OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE

                movwf   PRODL,ACCESS            ; PRODL is used as temp register

        _Pragma("asmend")

        ucScratch = PRODL;

        /*

         * Place a few bytes of known values on the bottom of the stack.

         * This is just useful for debugging.

         */

//      *pxTopOfStack-- = 0x11;

//      *pxTopOfStack-- = 0x22;

//      *pxTopOfStack-- = 0x33;

        /*

         * Simulate how the stack would look after a call to vPortYield()

         * generated by the compiler.

         */

        /*

         * First store the function parameters.  This is where the task expects

         * to find them when it starts running.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( (( unsigned short ) pvParameters >> 8) & 0x00ff );

        *pxTopOfStack-- = ( portSTACK_TYPE ) (  ( unsigned short ) pvParameters       & 0x00ff );

        /*

         * Next are all the registers that form part of the task context.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x11; /* STATUS. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x22; /* WREG. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x33; /* BSR. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x44; /* PRODH. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x55; /* PRODL. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x66; /* FSR0H. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x77; /* FSR0L. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x88; /* FSR1H. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x99; /* FSR1L. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xAA; /* TABLAT. */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0x00; /* TBLPTRU. */

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xCC; /* TBLPTRH. */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xDD; /* TBLPTRL. */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xEE; /* PCLATU. */

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0xFF; /* PCLATH. */

        /*

         * Next the compiler's scratchspace.

         */

        while(ucScratch-- > 0)

        {

                *pxTopOfStack-- = ( portSTACK_TYPE ) 0;

        }

        /*

         * The only function return address so far is the address of the task entry.

         * The order is TOSU/TOSH/TOSL. For devices > 64kB, TOSU is put on the

         * stack, too. TOSU is always written as zero here because wizC does not allow

         * functionpointers to point above 64kB in ROM.

         */

#if _ROMSIZE > 0x8000

        *pxTopOfStack-- = ( portSTACK_TYPE ) 0;

#endif

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( ( ( unsigned short ) pxCode >> 8 ) & 0x00ff );

        *pxTopOfStack-- = ( portSTACK_TYPE ) ( (   unsigned short ) pxCode        & 0x00ff );

        /*

         * Store the number of return addresses on the hardware stack.

         * So far only the address of the task entry point.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) 1;

        /*

         * The code generated by wizC does not maintain separate

         * stack and frame pointers. Therefore the portENTER_CRITICAL macro cannot

         * use the stack as per other ports.  Instead a variable is used to keep

         * track of the critical section nesting.  This variable has to be stored

         * as part of the task context and is initially set to zero.

         */

        *pxTopOfStack-- = ( portSTACK_TYPE ) portNO_CRITICAL_SECTION_NESTING;

        return pxTopOfStack;

}

/*-----------------------------------------------------------*/

unsigned short usPortCALCULATE_MINIMAL_STACK_SIZE( void )

{

        /*

         * Fetch the size of compiler's scratchspace.

         */

        _Pragma("asm")

                movlw   OVERHEADPAGE0-LOCOPTSIZE+MAXLOCOPTSIZE

                movlb   usCalcMinStackSize>>8

                movwf   usCalcMinStackSize,BANKED

        _Pragma("asmend")

        /*

         * Add minimum needed stackspace

         */

        usCalcMinStackSize      +=      ( portSTACK_FSR_BYTES )

                +       ( portSTACK_MINIMAL_CALLRETURN_DEPTH * portSTACK_CALLRETURN_ENTRY_SIZE )

                +       ( portSTACK_OTHER_BYTES );

        return(usCalcMinStackSize);

}

/*-----------------------------------------------------------*/

portBASE_TYPE xPortStartScheduler( void )

{

        extern void portSetupTick( void );

        /*

         * Setup a timer for the tick ISR for the preemptive scheduler.

         */

        portSetupTick();

        /*

         * Restore the context of the first task to run.

         */

        portRESTORE_CONTEXT();

        /*

         * This point should never be reached during execution.

         */

        return pdTRUE;

}

/*-----------------------------------------------------------*/

void vPortEndScheduler( void )

{

        /*

         * It is unlikely that the scheduler for the PIC port will get stopped

         * once running. When called a reset is done which is probably the

         * most valid action.

         */

        _Pragma(asmline reset);

}

/*-----------------------------------------------------------*/

/*

 * Manual context switch.  This is similar to the tick context switch,

 * but does not increment the tick count.  It must be identical to the

 * tick context switch in how it stores the stack of a task.

 */

void vPortYield( void )

{

        /*

         * Save the context of the current task.

         */

        portSAVE_CONTEXT( portINTERRUPTS_UNCHANGED );

        /*

         * Switch to the highest priority task that is ready to run.

         */

        vTaskSwitchContext();

        /*

         * Start executing the task we have just switched to.

         */

        portRESTORE_CONTEXT();

}

/*-----------------------------------------------------------*/

void *pvPortMalloc( unsigned short usWantedSize )

{

void *pvReturn;

        vTaskSuspendAll();

        {

                pvReturn = malloc( ( malloc_t ) usWantedSize );

        }

        xTaskResumeAll();

        return pvReturn;

}

void vPortFree( void *pv )

{

        if( pv )

        {

                vTaskSuspendAll();

                {

                        free( pv );

                }

                xTaskResumeAll();

        }

}