2 FreeRTOS.org V4.7.2 - Copyright (C) 2003-2008 Richard Barry.
\r
4 This file is part of the FreeRTOS.org distribution.
\r
6 FreeRTOS.org is free software; you can redistribute it and/or modify
\r
7 it under the terms of the GNU General Public License as published by
\r
8 the Free Software Foundation; either version 2 of the License, or
\r
9 (at your option) any later version.
\r
11 FreeRTOS.org is distributed in the hope that it will be useful,
\r
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
\r
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
\r
14 GNU General Public License for more details.
\r
16 You should have received a copy of the GNU General Public License
\r
17 along with FreeRTOS.org; if not, write to the Free Software
\r
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
\r
20 A special exception to the GPL can be applied should you wish to distribute
\r
21 a combined work that includes FreeRTOS.org, without being obliged to provide
\r
22 the source code for any proprietary components. See the licensing section
\r
23 of http://www.FreeRTOS.org for full details of how and when the exception
\r
26 ***************************************************************************
\r
28 Please ensure to read the configuration and relevant port sections of the
\r
29 online documentation.
\r
31 +++ http://www.FreeRTOS.org +++
\r
32 Documentation, latest information, license and contact details.
\r
34 +++ http://www.SafeRTOS.com +++
\r
35 A version that is certified for use in safety critical systems.
\r
37 +++ http://www.OpenRTOS.com +++
\r
38 Commercial support, development, porting, licensing and training services.
\r
40 ***************************************************************************
\r
43 /* Scheduler includes. */
\r
44 #include "FreeRTOS.h"
\r
48 /*-----------------------------------------------------------
\r
49 * Implementation of functions defined in portable.h for the HCS12 port.
\r
50 *----------------------------------------------------------*/
\r
54 * Configure a timer to generate the RTOS tick at the frequency specified
\r
55 * within FreeRTOSConfig.h.
\r
57 static void prvSetupTimerInterrupt( void );
\r
59 /* Interrupt service routines have to be in non-banked memory - as does the
\r
60 scheduler startup function. */
\r
61 #pragma CODE_SEG __NEAR_SEG NON_BANKED
\r
63 /* Manual context switch function. This is the SWI ISR. */
\r
64 void interrupt vPortYield( void );
\r
66 /* Tick context switch function. This is the timer ISR. */
\r
67 void interrupt vPortTickInterrupt( void );
\r
69 /* Simply called by xPortStartScheduler(). xPortStartScheduler() does not
\r
70 start the scheduler directly because the header file containing the
\r
71 xPortStartScheduler() prototype is part of the common kernel code, and
\r
72 therefore cannot use the CODE_SEG pragma. */
\r
73 static portBASE_TYPE xBankedStartScheduler( void );
\r
75 #pragma CODE_SEG DEFAULT
\r
77 /* Calls to portENTER_CRITICAL() can be nested. When they are nested the
\r
78 critical section should not be left (i.e. interrupts should not be re-enabled)
\r
79 until the nesting depth reaches 0. This variable simply tracks the nesting
\r
80 depth. Each task maintains it's own critical nesting depth variable so
\r
81 uxCriticalNesting is saved and restored from the task stack during a context
\r
83 volatile unsigned portBASE_TYPE uxCriticalNesting = 0xff;
\r
85 /*-----------------------------------------------------------*/
\r
88 * See header file for description.
\r
90 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
\r
93 Place a few bytes of known values on the bottom of the stack.
\r
94 This can be uncommented to provide useful stack markers when debugging.
\r
96 *pxTopOfStack = ( portSTACK_TYPE ) 0x11;
\r
98 *pxTopOfStack = ( portSTACK_TYPE ) 0x22;
\r
100 *pxTopOfStack = ( portSTACK_TYPE ) 0x33;
\r
106 /* Setup the initial stack of the task. The stack is set exactly as
\r
107 expected by the portRESTORE_CONTEXT() macro. In this case the stack as
\r
108 expected by the HCS12 RTI instruction. */
\r
111 /* The address of the task function is placed in the stack byte at a time. */
\r
112 *pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pxCode) ) + 1 );
\r
114 *pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pxCode) ) + 0 );
\r
117 /* Next are all the registers that form part of the task context. */
\r
120 *pxTopOfStack = ( portSTACK_TYPE ) 0xff;
\r
122 *pxTopOfStack = ( portSTACK_TYPE ) 0xee;
\r
126 *pxTopOfStack = ( portSTACK_TYPE ) 0xdd;
\r
128 *pxTopOfStack = ( portSTACK_TYPE ) 0xcc;
\r
131 /* A register contains parameter high byte. */
\r
132 *pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pvParameters) ) + 0 );
\r
135 /* B register contains parameter low byte. */
\r
136 *pxTopOfStack = ( portSTACK_TYPE ) *( ((portSTACK_TYPE *) (&pvParameters) ) + 1 );
\r
139 /* CCR: Note that when the task starts interrupts will be enabled since
\r
140 "I" bit of CCR is cleared */
\r
141 *pxTopOfStack = ( portSTACK_TYPE ) 0x00;
\r
144 #ifdef BANKED_MODEL
\r
145 /* The page of the task. */
\r
146 *pxTopOfStack = ( portSTACK_TYPE ) ( ( int ) pxCode );
\r
150 /* Finally the critical nesting depth is initialised with 0 (not within
\r
151 a critical section). */
\r
152 *pxTopOfStack = ( portSTACK_TYPE ) 0x00;
\r
154 return pxTopOfStack;
\r
156 /*-----------------------------------------------------------*/
\r
158 void vPortEndScheduler( void )
\r
160 /* It is unlikely that the HCS12 port will get stopped. */
\r
162 /*-----------------------------------------------------------*/
\r
164 static void prvSetupTimerInterrupt( void )
\r
166 TickTimer_SetFreqHz( configTICK_RATE_HZ );
\r
167 TickTimer_Enable();
\r
169 /*-----------------------------------------------------------*/
\r
171 portBASE_TYPE xPortStartScheduler( void )
\r
173 /* xPortStartScheduler() does not start the scheduler directly because
\r
174 the header file containing the xPortStartScheduler() prototype is part
\r
175 of the common kernel code, and therefore cannot use the CODE_SEG pragma.
\r
176 Instead it simply calls the locally defined xBankedStartScheduler() -
\r
177 which does use the CODE_SEG pragma. */
\r
179 return xBankedStartScheduler();
\r
181 /*-----------------------------------------------------------*/
\r
183 #pragma CODE_SEG __NEAR_SEG NON_BANKED
\r
185 static portBASE_TYPE xBankedStartScheduler( void )
\r
187 /* Configure the timer that will generate the RTOS tick. Interrupts are
\r
188 disabled when this function is called. */
\r
189 prvSetupTimerInterrupt();
\r
191 /* Restore the context of the first task. */
\r
192 portRESTORE_CONTEXT();
\r
194 /* Simulate the end of an interrupt to start the scheduler off. */
\r
197 /* Should not get here! */
\r
200 /*-----------------------------------------------------------*/
\r
203 * Context switch functions. These are both interrupt service routines.
\r
207 * Manual context switch forced by calling portYIELD(). This is the SWI
\r
210 void interrupt vPortYield( void )
\r
212 portSAVE_CONTEXT();
\r
213 vTaskSwitchContext();
\r
214 portRESTORE_CONTEXT();
\r
216 /*-----------------------------------------------------------*/
\r
219 * RTOS tick interrupt service routine. If the cooperative scheduler is
\r
220 * being used then this simply increments the tick count. If the
\r
221 * preemptive scheduler is being used a context switch can occur.
\r
223 void interrupt vPortTickInterrupt( void )
\r
225 #if configUSE_PREEMPTION == 1
\r
227 /* A context switch might happen so save the context. */
\r
228 portSAVE_CONTEXT();
\r
230 /* Increment the tick ... */
\r
231 vTaskIncrementTick();
\r
233 /* ... then see if the new tick value has necessitated a
\r
235 vTaskSwitchContext();
\r
239 /* Restore the context of a task - which may be a different task
\r
240 to that interrupted. */
\r
241 portRESTORE_CONTEXT();
\r
245 vTaskIncrementTick();
\r
251 #pragma CODE_SEG DEFAULT
\r