/* FreeRTOS.org V4.7.1 - 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. *************************************************************************** */ /* Changes from V4.2.1 + Introduced the configKERNEL_INTERRUPT_PRIORITY definition. */ /*----------------------------------------------------------- * Implementation of functions defined in portable.h for the PIC24 port. *----------------------------------------------------------*/ /* Scheduler include files. */ #include "FreeRTOS.h" #include "task.h" /* Hardware specifics. */ #define portBIT_SET 1 #define portTIMER_PRESCALE 8 #define portINITIAL_SR 0 /* Defined for backward compatability with project created prior to FreeRTOS.org V4.3.0. */ #ifndef configKERNEL_INTERRUPT_PRIORITY #define configKERNEL_INTERRUPT_PRIORITY 1 #endif /* The program counter is only 23 bits. */ #define portUNUSED_PR_BITS 0x7f /* Records the nesting depth of calls to portENTER_CRITICAL(). */ unsigned portBASE_TYPE uxCriticalNesting = 0xef; #if configKERNEL_INTERRUPT_PRIORITY != 1 #error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 ) #endif #ifdef MPLAB_PIC24_PORT #define portRESTORE_CONTEXT() \ asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \ "MOV [W0], W15 \n" \ "POP W0 \n" /* Restore the critical nesting counter for the task. */ \ "MOV W0, _uxCriticalNesting \n" \ "POP PSVPAG \n" \ "POP CORCON \n" \ "POP TBLPAG \n" \ "POP RCOUNT \n" /* Restore the registers from the stack. */ \ "POP W14 \n" \ "POP.D W12 \n" \ "POP.D W10 \n" \ "POP.D W8 \n" \ "POP.D W6 \n" \ "POP.D W4 \n" \ "POP.D W2 \n" \ "POP.D W0 \n" \ "POP SR " ); #define portSAVE_CONTEXT() \ asm volatile( "PUSH SR \n" /* Save the SR used by the task.... */ \ "PUSH W0 \n" /* ....then disable interrupts. */ \ "MOV #32, W0 \n" \ "MOV W0, SR \n" \ "PUSH W1 \n" /* Save registers to the stack. */ \ "PUSH.D W2 \n" \ "PUSH.D W4 \n" \ "PUSH.D W6 \n" \ "PUSH.D W8 \n" \ "PUSH.D W10 \n" \ "PUSH.D W12 \n" \ "PUSH W14 \n" \ "PUSH RCOUNT \n" \ "PUSH TBLPAG \n" \ "PUSH CORCON \n" \ "PUSH PSVPAG \n" \ "MOV _uxCriticalNesting, W0 \n" /* Save the critical nesting counter for the task. */ \ "PUSH W0 \n" \ "MOV _pxCurrentTCB, W0 \n" /* Save the new top of stack into the TCB. */ \ "MOV W15, [W0] "); #endif /* MPLAB_PIC24_PORT */ #ifdef MPLAB_DSPIC_PORT #define portRESTORE_CONTEXT() \ asm volatile( "MOV _pxCurrentTCB, W0 \n" /* Restore the stack pointer for the task. */ \ "MOV [W0], W15 \n" \ "POP W0 \n" /* Restore the critical nesting counter for the task. */ \ "MOV W0, _uxCriticalNesting \n" \ "POP PSVPAG \n" \ "POP CORCON \n" \ "POP DOENDH \n" \ "POP DOENDL \n" \ "POP DOSTARTH \n" \ "POP DOSTARTL \n" \ "POP DCOUNT \n" \ "POP ACCBU \n" \ "POP ACCBH \n" \ "POP ACCBL \n" \ "POP ACCAU \n" \ "POP ACCAH \n" \ "POP ACCAL \n" \ "POP TBLPAG \n" \ "POP RCOUNT \n" /* Restore the registers from the stack. */ \ "POP W14 \n" \ "POP.D W12 \n" \ "POP.D W10 \n" \ "POP.D W8 \n" \ "POP.D W6 \n" \ "POP.D W4 \n" \ "POP.D W2 \n" \ "POP.D W0 \n" \ "POP SR " ); #define portSAVE_CONTEXT() \ asm volatile( "PUSH SR \n" /* Save the SR used by the task.... */ \ "PUSH W0 \n" /* ....then disable interrupts. */ \ "MOV #32, W0 \n" \ "MOV W0, SR \n" \ "PUSH W1 \n" /* Save registers to the stack. */ \ "PUSH.D W2 \n" \ "PUSH.D W4 \n" \ "PUSH.D W6 \n" \ "PUSH.D W8 \n" \ "PUSH.D W10 \n" \ "PUSH.D W12 \n" \ "PUSH W14 \n" \ "PUSH RCOUNT \n" \ "PUSH TBLPAG \n" \ "PUSH ACCAL \n" \ "PUSH ACCAH \n" \ "PUSH ACCAU \n" \ "PUSH ACCBL \n" \ "PUSH ACCBH \n" \ "PUSH ACCBU \n" \ "PUSH DCOUNT \n" \ "PUSH DOSTARTL \n" \ "PUSH DOSTARTH \n" \ "PUSH DOENDL \n" \ "PUSH DOENDH \n" \ "PUSH CORCON \n" \ "PUSH PSVPAG \n" \ "MOV _uxCriticalNesting, W0 \n" /* Save the critical nesting counter for the task. */ \ "PUSH W0 \n" \ "MOV _pxCurrentTCB, W0 \n" /* Save the new top of stack into the TCB. */ \ "MOV W15, [W0] " ); #endif /* MPLAB_DSPIC_PORT */ /* * Setup the timer used to generate the tick interrupt. */ static void prvSetupTimerInterrupt( void ); /* * See header file for description. */ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) { unsigned portSHORT usCode; portBASE_TYPE i; const portSTACK_TYPE xInitialStack[] = { 0x1111, /* W1 */ 0x2222, /* W2 */ 0x3333, /* W3 */ 0x4444, /* W4 */ 0x5555, /* W5 */ 0x6666, /* W6 */ 0x7777, /* W7 */ 0x8888, /* W8 */ 0x9999, /* W9 */ 0xaaaa, /* W10 */ 0xbbbb, /* W11 */ 0xcccc, /* W12 */ 0xdddd, /* W13 */ 0xeeee, /* W14 */ 0xcdce, /* RCOUNT */ 0xabac, /* TBLPAG */ /* dsPIC specific registers. */ #ifdef MPLAB_DSPIC_PORT 0x0202, /* ACCAL */ 0x0303, /* ACCAH */ 0x0404, /* ACCAU */ 0x0505, /* ACCBL */ 0x0606, /* ACCBH */ 0x0707, /* ACCBU */ 0x0808, /* DCOUNT */ 0x090a, /* DOSTARTL */ 0x1010, /* DOSTARTH */ 0x1110, /* DOENDL */ 0x1212, /* DOENDH */ #endif }; /* Setup the stack as if a yield had occurred. Save the low bytes of the program counter. */ usCode = ( unsigned portSHORT ) pxCode; *pxTopOfStack = ( portSTACK_TYPE ) usCode; pxTopOfStack++; /* Save the high byte of the program counter. This will always be zero here as it is passed in a 16bit pointer. If the address is greater than 16 bits then the pointer will point to a jump table. */ *pxTopOfStack = ( portSTACK_TYPE ) 0; pxTopOfStack++; /* Status register with interrupts enabled. */ *pxTopOfStack = portINITIAL_SR; pxTopOfStack++; /* Parameters are passed in W0. */ *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; pxTopOfStack++; for( i = 0; i < ( sizeof( xInitialStack ) / sizeof( portSTACK_TYPE ) ); i++ ) { *pxTopOfStack = xInitialStack[ i ]; pxTopOfStack++; } *pxTopOfStack = CORCON; pxTopOfStack++; *pxTopOfStack = PSVPAG; pxTopOfStack++; /* Finally the critical nesting depth. */ *pxTopOfStack = 0x00; pxTopOfStack++; return pxTopOfStack; } /*-----------------------------------------------------------*/ portBASE_TYPE xPortStartScheduler( void ) { /* Setup a timer for the tick ISR. */ prvSetupTimerInterrupt(); /* Restore the context of the first task to run. */ portRESTORE_CONTEXT(); /* Simulate the end of the yield function. */ asm volatile ( "return" ); /* Should not reach here. */ return pdTRUE; } /*-----------------------------------------------------------*/ void vPortEndScheduler( void ) { /* It is unlikely that the scheduler for the PIC port will get stopped once running. If required disable the tick interrupt here, then return to xPortStartScheduler(). */ } /*-----------------------------------------------------------*/ /* * Manual context switch. This is similar to the tick context switch, * but does not increment the tick count. It must be identical to the * tick context switch in how it stores the stack of a task. */ void vPortYield( void ) { portSAVE_CONTEXT(); vTaskSwitchContext(); portRESTORE_CONTEXT(); } /*-----------------------------------------------------------*/ /* * Setup a timer for a regular tick. */ static void prvSetupTimerInterrupt( void ) { const unsigned portLONG ulCompareMatch = ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ; /* Prescale of 8. */ T1CON = 0; TMR1 = 0; PR1 = ( unsigned portSHORT ) ulCompareMatch; /* Setup timer 1 interrupt priority. */ IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY; /* Clear the interrupt as a starting condition. */ IFS0bits.T1IF = 0; /* Enable the interrupt. */ IEC0bits.T1IE = 1; /* Setup the prescale value. */ T1CONbits.TCKPS0 = 1; T1CONbits.TCKPS1 = 0; /* Start the timer. */ T1CONbits.TON = 1; } /*-----------------------------------------------------------*/ void vPortEnterCritical( void ) { portDISABLE_INTERRUPTS(); uxCriticalNesting++; } /*-----------------------------------------------------------*/ void vPortExitCritical( void ) { uxCriticalNesting--; if( uxCriticalNesting == 0 ) { portENABLE_INTERRUPTS(); } } /*-----------------------------------------------------------*/ void __attribute__((__interrupt__, auto_psv)) _T1Interrupt( void ) { vTaskIncrementTick(); /* Clear the timer interrupt. */ IFS0bits.T1IF = 0; #if configUSE_PREEMPTION == 1 portYIELD(); #endif }