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jeremybenn |
/*
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FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS books - available as PDF or paperback *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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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 it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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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 "FreeRTOS.h"
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#include "task.h"
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#include "mb91467d.h"
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/*-----------------------------------------------------------*/
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/* We require the address of the pxCurrentTCB variable, but don't want to know
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any details of its type. */
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typedef void tskTCB;
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extern volatile tskTCB * volatile pxCurrentTCB;
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/*-----------------------------------------------------------*/
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#pragma asm
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#macro SaveContext
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ORCCR #0x20 ;Switch to user stack
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ST RP,@-R15 ;Store RP
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STM0 (R7,R6,R5,R4,R3,R2,R1,R0) ;Store R7-R0
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STM1 (R14,R13,R12,R11,R10,R9,R8) ;Store R14-R8
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ST MDH, @-R15 ;Store MDH
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ST MDL, @-R15 ;Store MDL
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ANDCCR #0xDF ;Switch back to system stack
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LD @R15+,R0 ;Store PC to R0
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ORCCR #0x20 ;Switch to user stack
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ST R0,@-R15 ;Store PC to User stack
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ANDCCR #0xDF ;Switch back to system stack
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LD @R15+,R0 ;Store PS to R0
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ORCCR #0x20 ;Switch to user stack
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ST R0,@-R15 ;Store PS to User stack
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LDI #_pxCurrentTCB, R0 ;Get pxCurrentTCB address
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LD @R0, R0 ;Get the pxCurrentTCB->pxTopOfStack address
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ST R15,@R0 ;Store USP to pxCurrentTCB->pxTopOfStack
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ANDCCR #0xDF ;Switch back to system stack for the rest of tick ISR
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#endm
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#macro RestoreContext
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LDI #_pxCurrentTCB, R0 ;Get pxCurrentTCB address
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LD @R0, R0 ;Get the pxCurrentTCB->pxTopOfStack address
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ORCCR #0x20 ;Switch to user stack
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LD @R0, R15 ;Restore USP from pxCurrentTCB->pxTopOfStack
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LD @R15+,R0 ;Store PS to R0
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ANDCCR #0xDF ;Switch to system stack
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ST R0,@-R15 ;Store PS to system stack
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ORCCR #0x20 ;Switch to user stack
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LD @R15+,R0 ;Store PC to R0
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ANDCCR #0xDF ;Switch to system stack
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ST R0,@-R15 ;Store PC to system stack
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ORCCR #0x20 ;Switch back to retrieve the remaining context
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LD @R15+, MDL ;Restore MDL
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LD @R15+, MDH ;Restore MDH
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LDM1 (R14,R13,R12,R11,R10,R9,R8) ;Restore R14-R8
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LDM0 (R7,R6,R5,R4,R3,R2,R1,R0) ;Restore R7-R0
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LD @R15+, RP ;Restore RP
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ANDCCR #0xDF ;Switch back to system stack for the rest of tick ISR
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#endm
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#pragma endasm
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/*-----------------------------------------------------------*/
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/*
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* Perform hardware setup to enable ticks from timer 1,
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*/
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static void prvSetupTimerInterrupt( void );
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/*-----------------------------------------------------------*/
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/*
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* Initialise the stack of a task to look exactly as if a call to
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* portSAVE_CONTEXT had been called.
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*
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* See the header file portable.h.
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*/
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portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
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{
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/* Place a few bytes of known values on the bottom of the stack.
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This is just useful for debugging. */
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*pxTopOfStack = 0x11111111;
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pxTopOfStack--;
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*pxTopOfStack = 0x22222222;
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pxTopOfStack--;
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*pxTopOfStack = 0x33333333;
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pxTopOfStack--;
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/* This is a redundant push to the stack, it may be required if
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in some implementations of the compiler the parameter to the task
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is passed on to the stack rather than in R4 register. */
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*pxTopOfStack = (portSTACK_TYPE)(pvParameters);
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00000000; /* RP */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00007777; /* R7 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00006666; /* R6 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00005555; /* R5 */
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pxTopOfStack--;
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/* In the current implementation of the compiler the first
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parameter to the task (or function) is passed via R4 parameter
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to the task, hence the pvParameters pointer is copied into the R4
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register. See compiler manual section 4.6.2 for more information. */
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*pxTopOfStack = ( portSTACK_TYPE ) (pvParameters); /* R4 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00003333; /* R3 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00002222; /* R2 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00001111; /* R1 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00000001; /* R0 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x0000EEEE; /* R14 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x0000DDDD; /* R13 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x0000CCCC; /* R12 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x0000BBBB; /* R11 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x0000AAAA; /* R10 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00009999; /* R9 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x00008888; /* R8 */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x11110000; /* MDH */
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) 0x22220000; /* MDL */
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pxTopOfStack--;
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/* The start of the task code. */
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*pxTopOfStack = ( portSTACK_TYPE ) pxCode; /* PC */
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pxTopOfStack--;
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/* PS - User Mode, USP, ILM=31, Interrupts enabled */
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*pxTopOfStack = ( portSTACK_TYPE ) 0x001F0030; /* PS */
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return pxTopOfStack;
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}
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/*-----------------------------------------------------------*/
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portBASE_TYPE xPortStartScheduler( void )
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{
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/* Setup the hardware to generate the tick. */
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prvSetupTimerInterrupt();
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/* Restore the context of the first task that is going to run. */
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#pragma asm
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RestoreContext
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#pragma endasm
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/* Simulate a function call end as generated by the compiler. We will now
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jump to the start of the task the context of which we have just restored. */
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__asm(" reti ");
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/* Should not get here. */
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return pdFAIL;
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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/* Not implemented - unlikely to ever be required as there is nothing to
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return to. */
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}
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/*-----------------------------------------------------------*/
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static void prvSetupTimerInterrupt( void )
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{
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/* The peripheral clock divided by 32 is used by the timer. */
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const unsigned short usReloadValue = ( unsigned short ) ( ( ( configPER_CLOCK_HZ / configTICK_RATE_HZ ) / 32UL ) - 1UL );
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/* Setup RLT0 to generate a tick interrupt. */
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TMCSR0_CNTE = 0; /* Count Disable */
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TMCSR0_CSL = 0x2; /* CLKP/32 */
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TMCSR0_MOD = 0; /* Software trigger */
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TMCSR0_RELD = 1; /* Reload */
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TMCSR0_UF = 0; /* Clear underflow flag */
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TMRLR0 = usReloadValue;
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TMCSR0_INTE = 1; /* Interrupt Enable */
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TMCSR0_CNTE = 1; /* Count Enable */
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TMCSR0_TRG = 1; /* Trigger */
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PORTEN = 0x3; /* Port Enable */
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}
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/*-----------------------------------------------------------*/
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#if configUSE_PREEMPTION == 1
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/*
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* Tick ISR for preemptive scheduler. The tick count is incremented
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* after the context is saved. Then the context is switched if required,
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* and last the context of the task which is to be resumed is restored.
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*/
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#pragma asm
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.global _ReloadTimer0_IRQHandler
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_ReloadTimer0_IRQHandler:
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ANDCCR #0xEF ;Disable Interrupts
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SaveContext ;Save context
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ORCCR #0x10 ;Re-enable Interrupts
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LDI #0xFFFB,R1
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LDI #_tmcsr0, R0
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AND R1,@R0 ;Clear RLT0 interrupt flag
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CALL32 _vTaskIncrementTick,R12 ;Increment Tick
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CALL32 _vTaskSwitchContext,R12 ;Switch context if required
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ANDCCR #0xEF ;Disable Interrupts
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RestoreContext ;Restore context
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ORCCR #0x10 ;Re-enable Interrupts
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RETI
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#pragma endasm
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#else
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/*
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* Tick ISR for the cooperative scheduler. All this does is increment the
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* tick count. We don't need to switch context, this can only be done by
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* manual calls to taskYIELD();
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*/
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__interrupt void ReloadTimer0_IRQHandler( void )
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{
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/* Clear RLT0 interrupt flag */
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TMCSR0_UF = 0;
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vTaskIncrementTick();
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}
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#endif
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/*
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* Manual context switch. We can use a __nosavereg attribute as the context
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* would be saved by PortSAVE_CONTEXT(). The context is switched and then
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* the context of the new task is restored saved.
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*/
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#pragma asm
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.global _vPortYieldDelayed
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_vPortYieldDelayed:
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ANDCCR #0xEF ;Disable Interrupts
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SaveContext ;Save context
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ORCCR #0x10 ;Re-enable Interrupts
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LDI #_dicr, R0
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BANDL #0x0E, @R0 ;Clear Delayed interrupt flag
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CALL32 _vTaskSwitchContext,R12 ;Switch context if required
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ANDCCR #0xEF ;Disable Interrupts
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RestoreContext ;Restore context
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ORCCR #0x10 ;Re-enable Interrupts
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RETI
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#pragma endasm
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/*-----------------------------------------------------------*/
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/*
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* Manual context switch. We can use a __nosavereg attribute as the context
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* would be saved by PortSAVE_CONTEXT(). The context is switched and then
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* the context of the new task is restored saved.
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*/
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#pragma asm
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.global _vPortYield
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_vPortYield:
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SaveContext ;Save context
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CALL32 _vTaskSwitchContext,R12 ;Switch context if required
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RestoreContext ;Restore context
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RETI
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#pragma endasm
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/*-----------------------------------------------------------*/
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