mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
synced 2025-04-21 22:11:57 -04:00
233 lines
7.5 KiB
C
233 lines
7.5 KiB
C
/*
|
|
FreeRTOS.org V4.7.2 - Copyright (C) 2003-2008 Richard Barry.
|
|
|
|
This file is part of the FreeRTOS.org distribution.
|
|
|
|
FreeRTOS.org is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
FreeRTOS.org 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.org; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
A special exception to the GPL can be applied should you wish to distribute
|
|
a combined work that includes FreeRTOS.org, without being obliged to provide
|
|
the source code for any proprietary components. See the licensing section
|
|
of http://www.FreeRTOS.org for full details of how and when the exception
|
|
can be applied.
|
|
|
|
***************************************************************************
|
|
|
|
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 portPRESCALE_VALUE ( 16 )
|
|
#define portTIMER_COMPARE ( configCPU_CLOCK_HZ / ( configTICK_RATE_HZ * 4UL ) )
|
|
|
|
/* From the RDC data sheet. */
|
|
#define portENABLE_TIMER_AND_INTERRUPT ( unsigned portSHORT ) 0xe00b
|
|
#define portENABLE_TIMER ( unsigned portSHORT ) 0xC001
|
|
|
|
/* 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 );
|
|
|
|
/*-----------------------------------------------------------*/
|
|
/* See header file for description. */
|
|
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
|
|
{
|
|
portSTACK_TYPE DS_Reg = 0;
|
|
|
|
/* We need the true data segment. */
|
|
__asm{ MOV DS_Reg, DS };
|
|
|
|
/* 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_OFF( pvParameters );
|
|
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--;
|
|
|
|
*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;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/* 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. */
|
|
portEND_SWITCHING_ISR();
|
|
|
|
/* 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. */
|
|
portEND_SWITCHING_ISR();
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
void vPortEndScheduler( void )
|
|
{
|
|
/* Not implemented. */
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
static void prvSetupTimerInterrupt( void )
|
|
{
|
|
const unsigned portLONG ulCompareValue = portTIMER_COMPARE;
|
|
unsigned portSHORT usTimerCompare;
|
|
|
|
usTimerCompare = ( unsigned portSHORT ) ( ulCompareValue >> 4 );
|
|
t2_init( portENABLE_TIMER, portPRESCALE_VALUE, NULL );
|
|
|
|
#if( configUSE_PREEMPTION == 1 )
|
|
/* Tick service routine used by the scheduler when preemptive scheduling is
|
|
being used. */
|
|
t1_init( portENABLE_TIMER_AND_INTERRUPT, usTimerCompare, usTimerCompare, prvPreemptiveTick );
|
|
#else
|
|
/* Tick service routine used by the scheduler when cooperative scheduling is
|
|
being used. */
|
|
t1_init( portENABLE_TIMER_AND_INTERRUPT, usTimerCompare, usTimerCompare, prvNonPreemptiveTick );
|
|
#endif
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|