/* | |
FreeRTOS V9.0.1 - Copyright (C) 2017 Real Time Engineers Ltd. | |
All rights reserved | |
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. | |
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 modification 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. !<< | |
*************************************************************************** | |
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. Full license text is available on the following | |
link: http://www.freertos.org/a00114.html | |
*************************************************************************** | |
* * | |
* FreeRTOS provides completely free yet professionally developed, * | |
* robust, strictly quality controlled, supported, and cross * | |
* platform software that is more than just the market leader, it * | |
* is the industry's de facto standard. * | |
* * | |
* Help yourself get started quickly while simultaneously helping * | |
* to support the FreeRTOS project by purchasing a FreeRTOS * | |
* tutorial book, reference manual, or both: * | |
* http://www.FreeRTOS.org/Documentation * | |
* * | |
*************************************************************************** | |
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading | |
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defined configASSERT()? | |
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mission critical applications that require provable dependability. | |
1 tab == 4 spaces! | |
*/ | |
/* | |
Changes from V1.00: | |
+ Call to taskYIELD() from within tick ISR has been replaced by the more | |
efficient portSWITCH_CONTEXT(). | |
+ ISR function definitions renamed to include the prv prefix. | |
Changes from V1.2.0: | |
+ portRESET_PIC() is now called last thing before the end of the preemptive | |
tick routine. | |
Changes from V2.6.1 | |
+ Replaced the sUsingPreemption variable with the configUSE_PREEMPTION | |
macro to be consistent with the later ports. | |
*/ | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the Flashlite 186 | |
* port. | |
*----------------------------------------------------------*/ | |
#include <stdlib.h> | |
#include <i86.h> | |
#include <dos.h> | |
#include <setjmp.h> | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "portasm.h" | |
/*lint -e950 Non ANSI reserved words okay in this file only. */ | |
#define portTIMER_EOI_TYPE ( 8 ) | |
#define portRESET_PIC() portOUTPUT_WORD( ( uint16_t ) 0xff22, portTIMER_EOI_TYPE ) | |
#define portTIMER_INT_NUMBER 0x12 | |
#define portTIMER_1_CONTROL_REGISTER ( ( uint16_t ) 0xff5e ) | |
#define portTIMER_0_CONTROL_REGISTER ( ( uint16_t ) 0xff56 ) | |
#define portTIMER_INTERRUPT_ENABLE ( ( uint16_t ) 0x2000 ) | |
/* Setup the hardware to generate the required tick frequency. */ | |
static void prvSetTickFrequency( uint32_t ulTickRateHz ); | |
/* Set the hardware back to the state as per before the scheduler started. */ | |
static void prvExitFunction( void ); | |
#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 ); | |
/*lint -e956 File scopes necessary here. */ | |
/* Set true when the vectors are set so the scheduler will service the tick. */ | |
static int16_t sSchedulerRunning = pdFALSE; | |
/* Points to the original routine installed on the vector we use for manual context switches. This is then used to restore the original routine during prvExitFunction(). */ | |
static void ( __interrupt __far *pxOldSwitchISR )(); | |
/* Used to restore the original DOS context when the scheduler is ended. */ | |
static jmp_buf xJumpBuf; | |
/*lint +e956 */ | |
/*-----------------------------------------------------------*/ | |
BaseType_t xPortStartScheduler( void ) | |
{ | |
/* This is called with interrupts already disabled. */ | |
/* Remember what was on the interrupts we are going to use | |
so we can put them back later if required. */ | |
pxOldSwitchISR = _dos_getvect( portSWITCH_INT_NUMBER ); | |
/* Put our manual switch (yield) function on a known | |
vector. */ | |
_dos_setvect( portSWITCH_INT_NUMBER, prvYieldProcessor ); | |
#if configUSE_PREEMPTION == 1 | |
{ | |
/* Put our tick switch function on the timer interrupt. */ | |
_dos_setvect( portTIMER_INT_NUMBER, prvPreemptiveTick ); | |
} | |
#else | |
{ | |
/* We want the timer interrupt to just increment the tick count. */ | |
_dos_setvect( portTIMER_INT_NUMBER, prvNonPreemptiveTick ); | |
} | |
#endif | |
prvSetTickFrequency( configTICK_RATE_HZ ); | |
/* Clean up function if we want to return to DOS. */ | |
if( setjmp( xJumpBuf ) != 0 ) | |
{ | |
prvExitFunction(); | |
sSchedulerRunning = pdFALSE; | |
} | |
else | |
{ | |
sSchedulerRunning = pdTRUE; | |
/* Kick off the scheduler by setting up the context of the first task. */ | |
portFIRST_CONTEXT(); | |
} | |
return sSchedulerRunning; | |
} | |
/*-----------------------------------------------------------*/ | |
/* The tick ISR used depend on whether or not the preemptive or cooperative | |
kernel is being used. */ | |
#if configUSE_PREEMPTION == 1 | |
static void __interrupt __far prvPreemptiveTick( void ) | |
{ | |
/* Get the scheduler to update the task states following the tick. */ | |
if( xTaskIncrementTick() != pdFALSE ) | |
{ | |
/* Switch in the context of the next task to be run. */ | |
portSWITCH_CONTEXT(); | |
} | |
/* Reset the PIC ready for the next time. */ | |
portRESET_PIC(); | |
} | |
#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. */ | |
xTaskIncrementTick(); | |
portRESET_PIC(); | |
} | |
#endif | |
/*-----------------------------------------------------------*/ | |
static void __interrupt __far prvYieldProcessor( void ) | |
{ | |
/* Switch in the context of the next task to be run. */ | |
portSWITCH_CONTEXT(); | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* Jump back to the processor state prior to starting the | |
scheduler. This means we are not going to be using a | |
task stack frame so the task can be deleted. */ | |
longjmp( xJumpBuf, 1 ); | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvExitFunction( void ) | |
{ | |
const uint16_t usTimerDisable = 0x0000; | |
uint16_t usTimer0Control; | |
/* Interrupts should be disabled here anyway - but no | |
harm in making sure. */ | |
portDISABLE_INTERRUPTS(); | |
if( sSchedulerRunning == pdTRUE ) | |
{ | |
/* Put back the switch interrupt routines that was in place | |
before the scheduler started. */ | |
_dos_setvect( portSWITCH_INT_NUMBER, pxOldSwitchISR ); | |
} | |
/* Disable the timer used for the tick to ensure the scheduler is | |
not called before restoring interrupts. There was previously nothing | |
on this timer so there is no old ISR to restore. */ | |
portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerDisable ); | |
/* Restart the DOS tick. */ | |
usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER ); | |
usTimer0Control |= portTIMER_INTERRUPT_ENABLE; | |
portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control ); | |
portENABLE_INTERRUPTS(); | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvSetTickFrequency( uint32_t ulTickRateHz ) | |
{ | |
const uint16_t usMaxCountRegister = 0xff5a; | |
const uint16_t usTimerPriorityRegister = 0xff32; | |
const uint16_t usTimerEnable = 0xC000; | |
const uint16_t usRetrigger = 0x0001; | |
const uint16_t usTimerHighPriority = 0x0000; | |
uint16_t usTimer0Control; | |
/* ( CPU frequency / 4 ) / clock 2 max count [inpw( 0xff62 ) = 7] */ | |
const uint32_t ulClockFrequency = 0x7f31a0; | |
uint32_t ulTimerCount = ulClockFrequency / ulTickRateHz; | |
portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerEnable | portTIMER_INTERRUPT_ENABLE | usRetrigger ); | |
portOUTPUT_WORD( usMaxCountRegister, ( uint16_t ) ulTimerCount ); | |
portOUTPUT_WORD( usTimerPriorityRegister, usTimerHighPriority ); | |
/* Stop the DOS tick - don't do this if you want to maintain a TOD clock. */ | |
usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER ); | |
usTimer0Control &= ~portTIMER_INTERRUPT_ENABLE; | |
portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control ); | |
} | |
/*lint +e950 */ | |