/* | |
FreeRTOS V5.4.0 - Copyright (C) 2003-2009 Richard Barry. | |
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. | |
Alternative commercial license and support terms are also available upon | |
request. See the licensing section of http://www.FreeRTOS.org for full | |
license details. | |
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. See the GNU General Public License for | |
more details. | |
You should have received a copy of the GNU General Public License along | |
with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59 | |
Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
*************************************************************************** | |
* * | |
* Looking for a quick start? Then check out the FreeRTOS eBook! * | |
* See http://www.FreeRTOS.org/Documentation for details * | |
* * | |
*************************************************************************** | |
1 tab == 4 spaces! | |
Please ensure to read the configuration and relevant port sections of the | |
online documentation. | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the Tern EE 186 | |
* port. | |
*----------------------------------------------------------*/ | |
/* Library includes. */ | |
#include <embedded.h> | |
#include <ae.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "portasm.h" | |
/* The timer increments every four clocks, hence the divide by 4. */ | |
#define portTIMER_COMPARE ( unsigned portSHORT ) ( ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) / ( unsigned portLONG ) 4 ) | |
/* From the RDC data sheet. */ | |
#define portENABLE_TIMER_AND_INTERRUPT ( unsigned portSHORT ) 0xe001 | |
/* Interrupt control. */ | |
#define portEIO_REGISTER 0xff22 | |
#define portCLEAR_INTERRUPT 0x0008 | |
/* Setup the hardware to generate the required tick frequency. */ | |
static void prvSetupTimerInterrupt( void ); | |
/* The ISR used depends on whether the preemptive or cooperative scheduler | |
is being used. */ | |
#if( configUSE_PREEMPTION == 1 ) | |
/* Tick service routine used by the scheduler when preemptive scheduling is | |
being used. */ | |
static void __interrupt __far prvPreemptiveTick( void ); | |
#else | |
/* Tick service routine used by the scheduler when cooperative scheduling is | |
being used. */ | |
static void __interrupt __far prvNonPreemptiveTick( void ); | |
#endif | |
/* Trap routine used by taskYIELD() to manually cause a context switch. */ | |
static void __interrupt __far prvYieldProcessor( void ); | |
/* The timer initialisation functions leave interrupts enabled, | |
which is not what we want. This ISR is installed temporarily in case | |
the timer fires before we get a change to disable interrupts again. */ | |
static void __interrupt __far prvDummyISR( void ); | |
/*-----------------------------------------------------------*/ | |
/* See header file for description. */ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
portSTACK_TYPE DS_Reg = 0; | |
/* Place a few bytes of known values on the bottom of the stack. | |
This is just useful for debugging. */ | |
*pxTopOfStack = 0x1111; | |
pxTopOfStack--; | |
*pxTopOfStack = 0x2222; | |
pxTopOfStack--; | |
*pxTopOfStack = 0x3333; | |
pxTopOfStack--; | |
/* We are going to start the scheduler using a return from interrupt | |
instruction to load the program counter, so first there would be the | |
function call with parameters preamble. */ | |
*pxTopOfStack = FP_SEG( pvParameters ); | |
pxTopOfStack--; | |
*pxTopOfStack = FP_OFF( pvParameters ); | |
pxTopOfStack--; | |
*pxTopOfStack = FP_SEG( pxCode ); | |
pxTopOfStack--; | |
*pxTopOfStack = FP_OFF( pxCode ); | |
pxTopOfStack--; | |
/* Next the status register and interrupt return address. */ | |
*pxTopOfStack = portINITIAL_SW; | |
pxTopOfStack--; | |
*pxTopOfStack = FP_SEG( pxCode ); | |
pxTopOfStack--; | |
*pxTopOfStack = FP_OFF( pxCode ); | |
pxTopOfStack--; | |
/* The remaining registers would be pushed on the stack by our context | |
switch function. These are loaded with values simply to make debugging | |
easier. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xAAAA; /* AX */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BX */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xCCCC; /* CX */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DX */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xEEEE; /* ES */ | |
pxTopOfStack--; | |
/* We need the true data segment. */ | |
__asm{ MOV DS_Reg, DS }; | |
*pxTopOfStack = DS_Reg; /* DS */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0x0123; /* SI */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DI */ | |
pxTopOfStack--; | |
*pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BP */ | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xPortStartScheduler( void ) | |
{ | |
/* This is called with interrupts already disabled. */ | |
/* Put our manual switch (yield) function on a known | |
vector. */ | |
setvect( portSWITCH_INT_NUMBER, prvYieldProcessor ); | |
/* Setup the tick interrupt. */ | |
prvSetupTimerInterrupt(); | |
/* Kick off the scheduler by setting up the context of the first task. */ | |
portFIRST_CONTEXT(); | |
/* Should not get here! */ | |
return pdFALSE; | |
} | |
/*-----------------------------------------------------------*/ | |
static void __interrupt __far prvDummyISR( void ) | |
{ | |
/* The timer initialisation functions leave interrupts enabled, | |
which is not what we want. This ISR is installed temporarily in case | |
the timer fires before we get a change to disable interrupts again. */ | |
outport( portEIO_REGISTER, portCLEAR_INTERRUPT ); | |
} | |
/*-----------------------------------------------------------*/ | |
/* The ISR used depends on whether the preemptive or cooperative scheduler | |
is being used. */ | |
#if( configUSE_PREEMPTION == 1 ) | |
static void __interrupt __far prvPreemptiveTick( void ) | |
{ | |
/* Get the scheduler to update the task states following the tick. */ | |
vTaskIncrementTick(); | |
/* Switch in the context of the next task to be run. */ | |
portSWITCH_CONTEXT(); | |
/* Reset interrupt. */ | |
outport( portEIO_REGISTER, portCLEAR_INTERRUPT ); | |
} | |
#else | |
static void __interrupt __far prvNonPreemptiveTick( void ) | |
{ | |
/* Same as preemptive tick, but the cooperative scheduler is being used | |
so we don't have to switch in the context of the next task. */ | |
vTaskIncrementTick(); | |
/* Reset interrupt. */ | |
outport( portEIO_REGISTER, portCLEAR_INTERRUPT ); | |
} | |
#endif | |
/*-----------------------------------------------------------*/ | |
static void __interrupt __far prvYieldProcessor( void ) | |
{ | |
/* Switch in the context of the next task to be run. */ | |
portSWITCH_CONTEXT(); | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* Not implemented. */ | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvSetupTimerInterrupt( void ) | |
{ | |
const unsigned portSHORT usTimerACompare = portTIMER_COMPARE, usTimerAMode = portENABLE_TIMER_AND_INTERRUPT; | |
const unsigned portSHORT usT2_IRQ = 0x13; | |
/* Configure the timer, the dummy handler is used here as the init | |
function leaves interrupts enabled. */ | |
t2_init( usTimerAMode, usTimerACompare, prvDummyISR ); | |
/* Disable interrupts again before installing the real handlers. */ | |
portDISABLE_INTERRUPTS(); | |
#if( configUSE_PREEMPTION == 1 ) | |
/* Tick service routine used by the scheduler when preemptive scheduling is | |
being used. */ | |
setvect( usT2_IRQ, prvPreemptiveTick ); | |
#else | |
/* Tick service routine used by the scheduler when cooperative scheduling is | |
being used. */ | |
setvect( usT2_IRQ, prvNonPreemptiveTick ); | |
#endif | |
} | |