/* | |
FreeRTOS V5.4.2 - Copyright (C) 2009 Real Time Engineers Ltd. | |
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. | |
*/ | |
/* GCC/HCS12 port by Jefferson L Smith, 2005 */ | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* Port includes */ | |
#include <sys/ports_def.h> | |
/*----------------------------------------------------------- | |
* Implementation of functions defined in portable.h for the HCS12 port. | |
*----------------------------------------------------------*/ | |
/* | |
* Configure a timer to generate the RTOS tick at the frequency specified | |
* within FreeRTOSConfig.h. | |
*/ | |
static void prvSetupTimerInterrupt( void ); | |
/* NOTE: Interrupt service routines must be in non-banked memory - as does the | |
scheduler startup function. */ | |
#define ATTR_NEAR __attribute__((near)) | |
/* Manual context switch function. This is the SWI ISR. */ | |
// __attribute__((interrupt)) | |
void ATTR_NEAR vPortYield( void ); | |
/* Tick context switch function. This is the timer ISR. */ | |
// __attribute__((interrupt)) | |
void ATTR_NEAR vPortTickInterrupt( void ); | |
/* Function in non-banked memory which actually switches to first task. */ | |
portBASE_TYPE ATTR_NEAR xStartSchedulerNear( void ); | |
/* Calls to portENTER_CRITICAL() can be nested. When they are nested the | |
critical section should not be left (i.e. interrupts should not be re-enabled) | |
until the nesting depth reaches 0. This variable simply tracks the nesting | |
depth. Each task maintains it's own critical nesting depth variable so | |
uxCriticalNesting is saved and restored from the task stack during a context | |
switch. */ | |
volatile unsigned portBASE_TYPE uxCriticalNesting = 0x80; // un-initialized | |
/*-----------------------------------------------------------*/ | |
/* | |
* See header file for description. | |
*/ | |
portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
{ | |
/* Setup the initial stack of the task. The stack is set exactly as | |
expected by the portRESTORE_CONTEXT() macro. In this case the stack as | |
expected by the HCS12 RTI instruction. */ | |
/* The address of the task function is placed in the stack byte at a time. */ | |
*pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pxCode) ) + 1 ); | |
*--pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pxCode) ) + 0 ); | |
/* Next are all the registers that form part of the task context. */ | |
/* Y register */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0xff; | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0xee; | |
/* X register */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0xdd; | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0xcc; | |
/* A register contains parameter high byte. */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pvParameters) ) + 0 ); | |
/* B register contains parameter low byte. */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pvParameters) ) + 1 ); | |
/* CCR: Note that when the task starts interrupts will be enabled since | |
"I" bit of CCR is cleared */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0x80; // keeps Stop disabled (MCU default) | |
/* tmp softregs used by GCC. Values right now don't matter. */ | |
__asm("\n\ | |
movw _.frame, 2,-%0 \n\ | |
movw _.tmp, 2,-%0 \n\ | |
movw _.z, 2,-%0 \n\ | |
movw _.xy, 2,-%0 \n\ | |
;movw _.d2, 2,-%0 \n\ | |
;movw _.d1, 2,-%0 \n\ | |
": "=A"(pxTopOfStack) : "0"(pxTopOfStack) ); | |
#ifdef BANKED_MODEL | |
/* The page of the task. */ | |
*--pxTopOfStack = 0x30; // can only directly start in PPAGE 0x30 | |
#endif | |
/* The critical nesting depth is initialised with 0 (meaning not in | |
a critical section). */ | |
*--pxTopOfStack = ( portSTACK_TYPE ) 0x00; | |
return pxTopOfStack; | |
} | |
/*-----------------------------------------------------------*/ | |
void vPortEndScheduler( void ) | |
{ | |
/* It is unlikely that the HCS12 port will get stopped. */ | |
} | |
/*-----------------------------------------------------------*/ | |
static void prvSetupTimerInterrupt( void ) | |
{ | |
/* Enable hardware RTI timer */ | |
/* Ignores configTICK_RATE_HZ */ | |
RTICTL = 0x50; // 16 MHz xtal: 976.56 Hz, 1024mS | |
CRGINT |= 0x80; // RTIE | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xPortStartScheduler( void ) | |
{ | |
/* xPortStartScheduler() does not start the scheduler directly because | |
the header file containing the xPortStartScheduler() prototype is part | |
of the common kernel code, and therefore cannot use the CODE_SEG pragma. | |
Instead it simply calls the locally defined xNearStartScheduler() - | |
which does use the CODE_SEG pragma. */ | |
short register d; | |
__asm ("jmp xStartSchedulerNear ; will never return": "=d"(d)); | |
return d; | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xStartSchedulerNear( void ) | |
{ | |
/* Configure the timer that will generate the RTOS tick. Interrupts are | |
disabled when this function is called. */ | |
prvSetupTimerInterrupt(); | |
/* Restore the context of the first task. */ | |
portRESTORE_CONTEXT(); | |
portISR_TAIL(); | |
/* Should not get here! */ | |
return pdFALSE; | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* Context switch functions. These are interrupt service routines. | |
*/ | |
/* | |
* Manual context switch forced by calling portYIELD(). This is the SWI | |
* handler. | |
*/ | |
void vPortYield( void ) | |
{ | |
portISR_HEAD(); | |
/* NOTE: This is the trap routine (swi) although not defined as a trap. | |
It will fill the stack the same way as an ISR in order to mix preemtion | |
and cooperative yield. */ | |
portSAVE_CONTEXT(); | |
vTaskSwitchContext(); | |
portRESTORE_CONTEXT(); | |
portISR_TAIL(); | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* RTOS tick interrupt service routine. If the cooperative scheduler is | |
* being used then this simply increments the tick count. If the | |
* preemptive scheduler is being used a context switch can occur. | |
*/ | |
void vPortTickInterrupt( void ) | |
{ | |
portISR_HEAD(); | |
/* Clear tick timer flag */ | |
CRGFLG = 0x80; | |
#if configUSE_PREEMPTION == 1 | |
{ | |
/* A context switch might happen so save the context. */ | |
portSAVE_CONTEXT(); | |
/* Increment the tick ... */ | |
vTaskIncrementTick(); | |
/* ... then see if the new tick value has necessitated a | |
context switch. */ | |
vTaskSwitchContext(); | |
/* Restore the context of a task - which may be a different task | |
to that interrupted. */ | |
portRESTORE_CONTEXT(); | |
} | |
#else | |
{ | |
vTaskIncrementTick(); | |
} | |
#endif | |
portISR_TAIL(); | |
} | |