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https://github.com/FreeRTOS/FreeRTOS-Kernel.git
synced 2025-08-20 01:58:32 -04:00
Re-sync with upstream and stripping away none kernel related.
This commit is contained in:
Yuhui Zheng
parent
9c0c37ab9b
commit
210b1ffcc8
13732 changed files with 49 additions and 7054697 deletions
288
portable/BCC/16BitDOS/PC/port.c
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288
portable/BCC/16BitDOS/PC/port.c
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/*
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* FreeRTOS Kernel V10.3.0
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*
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Changes from V2.6.1
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+ Replaced the sUsingPreemption variable with the configUSE_PREEMPTION
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macro to be consistent with the later ports.
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Changes from V4.0.1
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+ Add function prvSetTickFrequencyDefault() to set the DOS tick back to
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its proper value when the scheduler exits.
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*/
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#include <stdlib.h>
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#include <dos.h>
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#include <setjmp.h>
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#include "FreeRTOS.h"
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#include "task.h"
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#include "portasm.h"
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the industrial
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* PC port.
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*----------------------------------------------------------*/
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/*lint -e950 Non ANSI reserved words okay in this file only. */
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#define portTIMER_INT_NUMBER 0x08
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/* Setup hardware for required tick interrupt rate. */
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static void prvSetTickFrequency( uint32_t ulTickRateHz );
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/* Restore hardware to as it was prior to starting the scheduler. */
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static void prvExitFunction( void );
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/* Either chain to the DOS tick (which itself clears the PIC) or clear the PIC
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directly. We chain to the DOS tick as close as possible to the standard DOS
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tick rate. */
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static void prvPortResetPIC( void );
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/* The ISR used depends on whether the preemptive or cooperative
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scheduler is being used. */
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#if( configUSE_PREEMPTION == 1 )
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/* Tick service routine used by the scheduler when preemptive scheduling is
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being used. */
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static void __interrupt __far prvPreemptiveTick( void );
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#else
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/* Tick service routine used by the scheduler when cooperative scheduling is
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being used. */
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static void __interrupt __far prvNonPreemptiveTick( void );
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#endif
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/* Trap routine used by taskYIELD() to manually cause a context switch. */
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static void __interrupt __far prvYieldProcessor( void );
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/* Set the tick frequency back so the floppy drive works correctly when the
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scheduler exits. */
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static void prvSetTickFrequencyDefault( void );
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/*lint -e956 File scopes necessary here. */
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/* Used to signal when to chain to the DOS tick, and when to just clear the PIC ourselves. */
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static int16_t sDOSTickCounter;
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/* Set true when the vectors are set so the scheduler will service the tick. */
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static BaseType_t xSchedulerRunning = pdFALSE;
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/* 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(). */
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static void ( __interrupt __far *pxOldSwitchISR )();
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/* Points to the original routine installed on the vector we use to chain to the DOS tick. This is then used to restore the original routine during prvExitFunction(). */
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static void ( __interrupt __far *pxOldSwitchISRPlus1 )();
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/* Used to restore the original DOS context when the scheduler is ended. */
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static jmp_buf xJumpBuf;
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/*lint +e956 */
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/*-----------------------------------------------------------*/
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BaseType_t xPortStartScheduler( void )
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{
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pxISR pxOriginalTickISR;
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/* This is called with interrupts already disabled. */
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/* Remember what was on the interrupts we are going to use
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so we can put them back later if required. */
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pxOldSwitchISR = _dos_getvect( portSWITCH_INT_NUMBER );
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pxOriginalTickISR = _dos_getvect( portTIMER_INT_NUMBER );
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pxOldSwitchISRPlus1 = _dos_getvect( portSWITCH_INT_NUMBER + 1 );
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prvSetTickFrequency( configTICK_RATE_HZ );
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/* Put our manual switch (yield) function on a known
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vector. */
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_dos_setvect( portSWITCH_INT_NUMBER, prvYieldProcessor );
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/* Put the old tick on a different interrupt number so we can
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call it when we want. */
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_dos_setvect( portSWITCH_INT_NUMBER + 1, pxOriginalTickISR );
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/* The ISR used depends on whether the preemptive or cooperative
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scheduler is being used. */
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#if( configUSE_PREEMPTION == 1 )
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{
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/* Put our tick switch function on the timer interrupt. */
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_dos_setvect( portTIMER_INT_NUMBER, prvPreemptiveTick );
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}
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#else
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{
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/* We want the timer interrupt to just increment the tick count. */
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_dos_setvect( portTIMER_INT_NUMBER, prvNonPreemptiveTick );
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}
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#endif
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/* Setup a counter that is used to call the DOS interrupt as close
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to it's original frequency as can be achieved given our chosen tick
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frequency. */
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sDOSTickCounter = portTICKS_PER_DOS_TICK;
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/* Clean up function if we want to return to DOS. */
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if( setjmp( xJumpBuf ) != 0 )
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{
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prvExitFunction();
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xSchedulerRunning = pdFALSE;
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}
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else
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{
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xSchedulerRunning = pdTRUE;
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/* Kick off the scheduler by setting up the context of the first task. */
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portFIRST_CONTEXT();
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}
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return xSchedulerRunning;
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}
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/*-----------------------------------------------------------*/
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/* The ISR used depends on whether the preemptive or cooperative
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scheduler is being used. */
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#if( configUSE_PREEMPTION == 1 )
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static void __interrupt __far prvPreemptiveTick( void )
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{
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/* Get the scheduler to update the task states following the tick. */
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if( xTaskIncrementTick() != pdFALSE )
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{
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/* Switch in the context of the next task to be run. */
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portSWITCH_CONTEXT();
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}
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/* Reset the PIC ready for the next time. */
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prvPortResetPIC();
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}
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#else
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static void __interrupt __far prvNonPreemptiveTick( void )
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{
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/* Same as preemptive tick, but the cooperative scheduler is being used
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so we don't have to switch in the context of the next task. */
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xTaskIncrementTick();
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prvPortResetPIC();
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}
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#endif
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/*-----------------------------------------------------------*/
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static void __interrupt __far prvYieldProcessor( void )
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{
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/* Switch in the context of the next task to be run. */
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portSWITCH_CONTEXT();
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}
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/*-----------------------------------------------------------*/
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static void prvPortResetPIC( void )
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{
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/* We are going to call the DOS tick interrupt at as close a
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frequency to the normal DOS tick as possible. */
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/* WE SHOULD NOT DO THIS IF YIELD WAS CALLED. */
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--sDOSTickCounter;
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if( sDOSTickCounter <= 0 )
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{
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sDOSTickCounter = ( int16_t ) portTICKS_PER_DOS_TICK;
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__asm{ int portSWITCH_INT_NUMBER + 1 };
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}
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else
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{
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/* Reset the PIC as the DOS tick is not being called to
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do it. */
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__asm
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{
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mov al, 20H
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out 20H, al
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};
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}
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}
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/*-----------------------------------------------------------*/
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void vPortEndScheduler( void )
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{
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/* Jump back to the processor state prior to starting the
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scheduler. This means we are not going to be using a
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task stack frame so the task can be deleted. */
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longjmp( xJumpBuf, 1 );
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}
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/*-----------------------------------------------------------*/
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static void prvExitFunction( void )
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{
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void ( __interrupt __far *pxOriginalTickISR )();
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/* Interrupts should be disabled here anyway - but no
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harm in making sure. */
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portDISABLE_INTERRUPTS();
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if( xSchedulerRunning == pdTRUE )
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{
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/* Set the DOS tick back onto the timer ticker. */
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pxOriginalTickISR = _dos_getvect( portSWITCH_INT_NUMBER + 1 );
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_dos_setvect( portTIMER_INT_NUMBER, pxOriginalTickISR );
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prvSetTickFrequencyDefault();
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/* Put back the switch interrupt routines that was in place
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before the scheduler started. */
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_dos_setvect( portSWITCH_INT_NUMBER, pxOldSwitchISR );
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_dos_setvect( portSWITCH_INT_NUMBER + 1, pxOldSwitchISRPlus1 );
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}
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/* The tick timer is back how DOS wants it. We can re-enable
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interrupts without the scheduler being called. */
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portENABLE_INTERRUPTS();
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}
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/*-----------------------------------------------------------*/
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static void prvSetTickFrequency( uint32_t ulTickRateHz )
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{
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const uint16_t usPIT_MODE = ( uint16_t ) 0x43;
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const uint16_t usPIT0 = ( uint16_t ) 0x40;
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const uint32_t ulPIT_CONST = ( uint32_t ) 1193180UL;
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const uint16_t us8254_CTR0_MODE3 = ( uint16_t ) 0x36;
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uint32_t ulOutput;
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/* Setup the 8245 to tick at the wanted frequency. */
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portOUTPUT_BYTE( usPIT_MODE, us8254_CTR0_MODE3 );
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ulOutput = ulPIT_CONST / ulTickRateHz;
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portOUTPUT_BYTE( usPIT0, ( uint16_t )( ulOutput & ( uint32_t ) 0xff ) );
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ulOutput >>= 8;
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portOUTPUT_BYTE( usPIT0, ( uint16_t ) ( ulOutput & ( uint32_t ) 0xff ) );
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}
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/*-----------------------------------------------------------*/
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static void prvSetTickFrequencyDefault( void )
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{
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const uint16_t usPIT_MODE = ( uint16_t ) 0x43;
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const uint16_t usPIT0 = ( uint16_t ) 0x40;
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const uint16_t us8254_CTR0_MODE3 = ( uint16_t ) 0x36;
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portOUTPUT_BYTE( usPIT_MODE, us8254_CTR0_MODE3 );
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portOUTPUT_BYTE( usPIT0,0 );
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portOUTPUT_BYTE( usPIT0,0 );
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}
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/*lint +e950 */
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