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Update FreeRTOS version number to V7.5.3
[freertos] / FreeRTOS / Source / portable / MPLAB / PIC18F / port.c
1 /*\r
2     FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd. \r
3     All rights reserved\r
4 \r
5     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.\r
6 \r
7     ***************************************************************************\r
8      *                                                                       *\r
9      *    FreeRTOS provides completely free yet professionally developed,    *\r
10      *    robust, strictly quality controlled, supported, and cross          *\r
11      *    platform software that has become a de facto standard.             *\r
12      *                                                                       *\r
13      *    Help yourself get started quickly and support the FreeRTOS         *\r
14      *    project by purchasing a FreeRTOS tutorial book, reference          *\r
15      *    manual, or both from: http://www.FreeRTOS.org/Documentation        *\r
16      *                                                                       *\r
17      *    Thank you!                                                         *\r
18      *                                                                       *\r
19     ***************************************************************************\r
20 \r
21     This file is part of the FreeRTOS distribution.\r
22 \r
23     FreeRTOS is free software; you can redistribute it and/or modify it under\r
24     the terms of the GNU General Public License (version 2) as published by the\r
25     Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.\r
26 \r
27     >>! NOTE: The modification to the GPL is included to allow you to distribute\r
28     >>! a combined work that includes FreeRTOS without being obliged to provide\r
29     >>! the source code for proprietary components outside of the FreeRTOS\r
30     >>! kernel.\r
31 \r
32     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY\r
33     WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS\r
34     FOR A PARTICULAR PURPOSE.  Full license text is available from the following\r
35     link: http://www.freertos.org/a00114.html\r
36 \r
37     1 tab == 4 spaces!\r
38 \r
39     ***************************************************************************\r
40      *                                                                       *\r
41      *    Having a problem?  Start by reading the FAQ "My application does   *\r
42      *    not run, what could be wrong?"                                     *\r
43      *                                                                       *\r
44      *    http://www.FreeRTOS.org/FAQHelp.html                               *\r
45      *                                                                       *\r
46     ***************************************************************************\r
47 \r
48     http://www.FreeRTOS.org - Documentation, books, training, latest versions,\r
49     license and Real Time Engineers Ltd. contact details.\r
50 \r
51     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,\r
52     including FreeRTOS+Trace - an indispensable productivity tool, a DOS\r
53     compatible FAT file system, and our tiny thread aware UDP/IP stack.\r
54 \r
55     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High\r
56     Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS\r
57     licenses offer ticketed support, indemnification and middleware.\r
58 \r
59     http://www.SafeRTOS.com - High Integrity Systems also provide a safety\r
60     engineered and independently SIL3 certified version for use in safety and\r
61     mission critical applications that require provable dependability.\r
62 \r
63     1 tab == 4 spaces!\r
64 */\r
65 \r
66 /* \r
67 Changes between V1.2.4 and V1.2.5\r
68 \r
69         + Introduced portGLOBAL_INTERRUPT_FLAG definition to test the global \r
70           interrupt flag setting.  Using the two bits defined within\r
71           portINITAL_INTERRUPT_STATE was causing the w register to get clobbered\r
72           before the test was performed.\r
73 \r
74 Changes from V1.2.5\r
75 \r
76         + Set the interrupt vector address to 0x08.  Previously it was at the\r
77           incorrect address for compatibility mode of 0x18.\r
78 \r
79 Changes from V2.1.1\r
80 \r
81         + PCLATU and PCLATH are now saved as part of the context.  This allows\r
82           function pointers to be used within tasks.  Thanks to Javier Espeche\r
83           for the enhancement. \r
84 \r
85 Changes from V2.3.1\r
86 \r
87         + TABLAT is now saved as part of the task context.\r
88         \r
89 Changes from V3.2.0\r
90 \r
91         + TBLPTRU is now initialised to zero as the MPLAB compiler expects this\r
92           value and does not write to the register.\r
93 */\r
94 \r
95 /* Scheduler include files. */\r
96 #include "FreeRTOS.h"\r
97 #include "task.h"\r
98 \r
99 /* MPLAB library include file. */\r
100 #include "timers.h"\r
101 \r
102 /*-----------------------------------------------------------\r
103  * Implementation of functions defined in portable.h for the PIC port.\r
104  *----------------------------------------------------------*/\r
105 \r
106 /* Hardware setup for tick. */\r
107 #define portTIMER_FOSC_SCALE                    ( ( unsigned long ) 4 )\r
108 \r
109 /* Initial interrupt enable state for newly created tasks.  This value is\r
110 copied into INTCON when a task switches in for the first time. */\r
111 #define portINITAL_INTERRUPT_STATE                      0xc0\r
112 \r
113 /* Just the bit within INTCON for the global interrupt flag. */\r
114 #define portGLOBAL_INTERRUPT_FLAG                       0x80\r
115 \r
116 /* Constant used for context switch macro when we require the interrupt \r
117 enable state to be unchanged when the interrupted task is switched back in. */\r
118 #define portINTERRUPTS_UNCHANGED                        0x00\r
119 \r
120 /* Some memory areas get saved as part of the task context.  These memory\r
121 area's get used by the compiler for temporary storage, especially when \r
122 performing mathematical operations, or when using 32bit data types.  This\r
123 constant defines the size of memory area which must be saved. */\r
124 #define portCOMPILER_MANAGED_MEMORY_SIZE        ( ( unsigned char ) 0x13 )\r
125 \r
126 /* We require the address of the pxCurrentTCB variable, but don't want to know\r
127 any details of its type. */\r
128 typedef void tskTCB;\r
129 extern volatile tskTCB * volatile pxCurrentTCB;\r
130 \r
131 /* IO port constants. */\r
132 #define portBIT_SET             ( ( unsigned char ) 1 )\r
133 #define portBIT_CLEAR   ( ( unsigned char ) 0 )\r
134 \r
135 /*\r
136  * The serial port ISR's are defined in serial.c, but are called from portable\r
137  * as they use the same vector as the tick ISR.\r
138  */\r
139 void vSerialTxISR( void );\r
140 void vSerialRxISR( void );\r
141 \r
142 /*\r
143  * Perform hardware setup to enable ticks.\r
144  */\r
145 static void prvSetupTimerInterrupt( void );\r
146 \r
147 /* \r
148  * ISR to maintain the tick, and perform tick context switches if the\r
149  * preemptive scheduler is being used.\r
150  */\r
151 static void prvTickISR( void );\r
152 \r
153 /*\r
154  * ISR placed on the low priority vector.  This calls the appropriate ISR for\r
155  * the actual interrupt.\r
156  */\r
157 static void prvLowInterrupt( void );\r
158 \r
159 /* \r
160  * Macro that pushes all the registers that make up the context of a task onto\r
161  * the stack, then saves the new top of stack into the TCB.\r
162  * \r
163  * If this is called from an ISR then the interrupt enable bits must have been \r
164  * set for the ISR to ever get called.  Therefore we want to save the INTCON\r
165  * register with the enable bits forced to be set - and ucForcedInterruptFlags \r
166  * must contain these bit settings.  This means the interrupts will again be\r
167  * enabled when the interrupted task is switched back in.\r
168  *\r
169  * If this is called from a manual context switch (i.e. from a call to yield),\r
170  * then we want to save the INTCON so it is restored with its current state,\r
171  * and ucForcedInterruptFlags must be 0.  This allows a yield from within\r
172  * a critical section.\r
173  *\r
174  * The compiler uses some locations at the bottom of the memory for temporary\r
175  * storage during math and other computations.  This is especially true if\r
176  * 32bit data types are utilised (as they are by the scheduler).  The .tmpdata\r
177  * and MATH_DATA sections have to be stored in there entirety as part of a task\r
178  * context.  This macro stores from data address 0x00 to \r
179  * portCOMPILER_MANAGED_MEMORY_SIZE.  This is sufficient for the demo \r
180  * applications but you should check the map file for your project to ensure \r
181  * this is sufficient for your needs.  It is not clear whether this size is \r
182  * fixed for all compilations or has the potential to be program specific.\r
183  */\r
184 #define portSAVE_CONTEXT( ucForcedInterruptFlags )                                                              \\r
185 {                                                                                                                                                               \\r
186         _asm                                                                                                                                            \\r
187                 /* Save the status and WREG registers first, as these will get modified \\r
188                 by the operations below. */                                                                                             \\r
189                 MOVFF   WREG, PREINC1                                                                                                   \\r
190                 MOVFF   STATUS, PREINC1                                                                                                 \\r
191                 /* Save the INTCON register with the appropriate bits forced if                 \\r
192                 necessary - as described above. */                                                                              \\r
193                 MOVFF   INTCON, WREG                                                                                                    \\r
194                 IORLW   ucForcedInterruptFlags                                                                                  \\r
195                 MOVFF   WREG, PREINC1                                                                                                   \\r
196         _endasm                                                                                                                                         \\r
197                                                                                                                                                                 \\r
198         portDISABLE_INTERRUPTS();                                                                                                       \\r
199                                                                                                                                                                 \\r
200         _asm                                                                                                                                            \\r
201                 /* Store the necessary registers to the stack. */                                               \\r
202                 MOVFF   BSR, PREINC1                                                                                                    \\r
203                 MOVFF   FSR2L, PREINC1                                                                                                  \\r
204                 MOVFF   FSR2H, PREINC1                                                                                                  \\r
205                 MOVFF   FSR0L, PREINC1                                                                                                  \\r
206                 MOVFF   FSR0H, PREINC1                                                                                                  \\r
207                 MOVFF   TABLAT, PREINC1                                                                                                 \\r
208                 MOVFF   TBLPTRU, PREINC1                                                                                                \\r
209                 MOVFF   TBLPTRH, PREINC1                                                                                                \\r
210                 MOVFF   TBLPTRL, PREINC1                                                                                                \\r
211                 MOVFF   PRODH, PREINC1                                                                                                  \\r
212                 MOVFF   PRODL, PREINC1                                                                                                  \\r
213                 MOVFF   PCLATU, PREINC1                                                                                                 \\r
214                 MOVFF   PCLATH, PREINC1                                                                                                 \\r
215                 /* Store the .tempdata and MATH_DATA areas as described above. */               \\r
216                 CLRF    FSR0L, 0                                                                                                                \\r
217                 CLRF    FSR0H, 0                                                                                                                \\r
218                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
219                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
220                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
221                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
222                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
223                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
224                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
225                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
226                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
227                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
228                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
229                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
230                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
231                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
232                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
233                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
234                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
235                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
236                 MOVFF   POSTINC0, PREINC1                                                                                               \\r
237                 MOVFF   INDF0, PREINC1                                                                                                  \\r
238                 MOVFF   FSR0L, PREINC1                                                                                                  \\r
239                 MOVFF   FSR0H, PREINC1                                                                                                  \\r
240                 /* Store the hardware stack pointer in a temp register before we                \\r
241                 modify it. */                                                                                                                   \\r
242                 MOVFF   STKPTR, FSR0L                                                                                                   \\r
243         _endasm                                                                                                                                         \\r
244                                                                                                                                                                 \\r
245                 /* Store each address from the hardware stack. */                                               \\r
246                 while( STKPTR > ( unsigned char ) 0 )                                                           \\r
247                 {                                                                                                                                               \\r
248                         _asm                                                                                                                            \\r
249                                 MOVFF   TOSL, PREINC1                                                                                   \\r
250                                 MOVFF   TOSH, PREINC1                                                                                   \\r
251                                 MOVFF   TOSU, PREINC1                                                                                   \\r
252                                 POP                                                                                                                             \\r
253                         _endasm                                                                                                                         \\r
254                 }                                                                                                                                               \\r
255                                                                                                                                                                 \\r
256         _asm                                                                                                                                            \\r
257                 /* Store the number of addresses on the hardware stack (from the                \\r
258                 temporary register). */                                                                                                 \\r
259                 MOVFF   FSR0L, PREINC1                                                                                                  \\r
260                 MOVF    PREINC1, 1, 0                                                                                                   \\r
261         _endasm                                                                                                                                         \\r
262                                                                                                                                                                 \\r
263         /* Save the new top of the software stack in the TCB. */                                        \\r
264         _asm                                                                                                                                            \\r
265                 MOVFF   pxCurrentTCB, FSR0L                                                                                             \\r
266                 MOVFF   pxCurrentTCB + 1, FSR0H                                                                                 \\r
267                 MOVFF   FSR1L, POSTINC0                                                                                                 \\r
268                 MOVFF   FSR1H, POSTINC0                                                                                                 \\r
269         _endasm                                                                                                                                         \\r
270 }\r
271 /*-----------------------------------------------------------*/\r
272 \r
273 /*\r
274  * This is the reverse of portSAVE_CONTEXT.  See portSAVE_CONTEXT for more\r
275  * details.\r
276  */\r
277 #define portRESTORE_CONTEXT()                                                                                                   \\r
278 {                                                                                                                                                               \\r
279         _asm                                                                                                                                            \\r
280                 /* Set FSR0 to point to pxCurrentTCB->pxTopOfStack. */                                  \\r
281                 MOVFF   pxCurrentTCB, FSR0L                                                                                             \\r
282                 MOVFF   pxCurrentTCB + 1, FSR0H                                                                                 \\r
283                                                                                                                                                                 \\r
284                 /* De-reference FSR0 to set the address it holds into FSR1.                             \\r
285                 (i.e. *( pxCurrentTCB->pxTopOfStack ) ). */                                                             \\r
286                 MOVFF   POSTINC0, FSR1L                                                                                                 \\r
287                 MOVFF   POSTINC0, FSR1H                                                                                                 \\r
288                                                                                                                                                                 \\r
289                 /* How many return addresses are there on the hardware stack?  Discard  \\r
290                 the first byte as we are pointing to the next free space. */                    \\r
291                 MOVFF   POSTDEC1, FSR0L                                                                                                 \\r
292                 MOVFF   POSTDEC1, FSR0L                                                                                                 \\r
293         _endasm                                                                                                                                         \\r
294                                                                                                                                                                 \\r
295         /* Fill the hardware stack from our software stack. */                                          \\r
296         STKPTR = 0;                                                                                                                                     \\r
297                                                                                                                                                                 \\r
298         while( STKPTR < FSR0L )                                                                                                         \\r
299         {                                                                                                                                                       \\r
300                 _asm                                                                                                                                    \\r
301                         PUSH                                                                                                                            \\r
302                         MOVF    POSTDEC1, 0, 0                                                                                          \\r
303                         MOVWF   TOSU, 0                                                                                                         \\r
304                         MOVF    POSTDEC1, 0, 0                                                                                          \\r
305                         MOVWF   TOSH, 0                                                                                                         \\r
306                         MOVF    POSTDEC1, 0, 0                                                                                          \\r
307                         MOVWF   TOSL, 0                                                                                                         \\r
308                 _endasm                                                                                                                                 \\r
309         }                                                                                                                                                       \\r
310                                                                                                                                                                 \\r
311         _asm                                                                                                                                            \\r
312                 /* Restore the .tmpdata and MATH_DATA memory. */                                                \\r
313                 MOVFF   POSTDEC1, FSR0H                                                                                                 \\r
314                 MOVFF   POSTDEC1, FSR0L                                                                                                 \\r
315                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
316                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
317                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
318                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
319                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
320                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
321                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
322                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
323                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
324                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
325                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
326                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
327                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
328                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
329                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
330                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
331                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
332                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
333                 MOVFF   POSTDEC1, POSTDEC0                                                                                              \\r
334                 MOVFF   POSTDEC1, INDF0                                                                                                 \\r
335                 /* Restore the other registers forming the tasks context. */                    \\r
336                 MOVFF   POSTDEC1, PCLATH                                                                                                \\r
337                 MOVFF   POSTDEC1, PCLATU                                                                                                \\r
338                 MOVFF   POSTDEC1, PRODL                                                                                                 \\r
339                 MOVFF   POSTDEC1, PRODH                                                                                                 \\r
340                 MOVFF   POSTDEC1, TBLPTRL                                                                                               \\r
341                 MOVFF   POSTDEC1, TBLPTRH                                                                                               \\r
342                 MOVFF   POSTDEC1, TBLPTRU                                                                                               \\r
343                 MOVFF   POSTDEC1, TABLAT                                                                                                \\r
344                 MOVFF   POSTDEC1, FSR0H                                                                                                 \\r
345                 MOVFF   POSTDEC1, FSR0L                                                                                                 \\r
346                 MOVFF   POSTDEC1, FSR2H                                                                                                 \\r
347                 MOVFF   POSTDEC1, FSR2L                                                                                                 \\r
348                 MOVFF   POSTDEC1, BSR                                                                                                   \\r
349                 /* The next byte is the INTCON register.  Read this into WREG as some   \\r
350                 manipulation is required. */                                                                                    \\r
351                 MOVFF   POSTDEC1, WREG                                                                                                  \\r
352         _endasm                                                                                                                                         \\r
353                                                                                                                                                                 \\r
354         /* From the INTCON register, only the interrupt enable bits form part           \\r
355         of the tasks context.  It is perfectly legitimate for another task to           \\r
356         have modified any other bits.  We therefore only restore the top two bits.      \\r
357         */                                                                                                                                                      \\r
358         if( WREG & portGLOBAL_INTERRUPT_FLAG )                                                                          \\r
359         {                                                                                                                                                       \\r
360                 _asm                                                                                                                                    \\r
361                         MOVFF   POSTDEC1, STATUS                                                                                        \\r
362                         MOVFF   POSTDEC1, WREG                                                                                          \\r
363                         /* Return enabling interrupts. */                                                                       \\r
364                         RETFIE  0                                                                                                                       \\r
365                 _endasm                                                                                                                                 \\r
366         }                                                                                                                                                       \\r
367         else                                                                                                                                            \\r
368         {                                                                                                                                                       \\r
369                 _asm                                                                                                                                    \\r
370                         MOVFF   POSTDEC1, STATUS                                                                                        \\r
371                         MOVFF   POSTDEC1, WREG                                                                                          \\r
372                         /* Return without effecting interrupts.  The context may have           \\r
373                         been saved from a critical region. */                                                           \\r
374                         RETURN  0                                                                                                                       \\r
375                 _endasm                                                                                                                                 \\r
376         }                                                                                                                                                       \\r
377 }\r
378 /*-----------------------------------------------------------*/\r
379 \r
380 /* \r
381  * See header file for description. \r
382  */\r
383 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )\r
384 {\r
385 unsigned long ulAddress;\r
386 unsigned char ucBlock;\r
387 \r
388         /* Place a few bytes of known values on the bottom of the stack. \r
389         This is just useful for debugging. */\r
390 \r
391         *pxTopOfStack = 0x11;\r
392         pxTopOfStack++;\r
393         *pxTopOfStack = 0x22;\r
394         pxTopOfStack++;\r
395         *pxTopOfStack = 0x33;\r
396         pxTopOfStack++;\r
397 \r
398 \r
399         /* Simulate how the stack would look after a call to vPortYield() generated\r
400         by the compiler. \r
401 \r
402         First store the function parameters.  This is where the task will expect to\r
403         find them when it starts running. */\r
404         ulAddress = ( unsigned long ) pvParameters;\r
405         *pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff );\r
406         pxTopOfStack++;\r
407 \r
408         ulAddress >>= 8;\r
409         *pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff );\r
410         pxTopOfStack++;\r
411 \r
412         /* Next we just leave a space.  When a context is saved the stack pointer\r
413         is incremented before it is used so as not to corrupt whatever the stack\r
414         pointer is actually pointing to.  This is especially necessary during \r
415         function epilogue code generated by the compiler. */\r
416         *pxTopOfStack = 0x44;\r
417         pxTopOfStack++;\r
418 \r
419         /* Next are all the registers that form part of the task context. */\r
420         \r
421         *pxTopOfStack = ( portSTACK_TYPE ) 0x66; /* WREG. */\r
422         pxTopOfStack++;\r
423 \r
424         *pxTopOfStack = ( portSTACK_TYPE ) 0xcc; /* Status. */\r
425         pxTopOfStack++;\r
426 \r
427         /* INTCON is saved with interrupts enabled. */\r
428         *pxTopOfStack = ( portSTACK_TYPE ) portINITAL_INTERRUPT_STATE; /* INTCON */\r
429         pxTopOfStack++;\r
430 \r
431         *pxTopOfStack = ( portSTACK_TYPE ) 0x11; /* BSR. */\r
432         pxTopOfStack++;\r
433 \r
434         *pxTopOfStack = ( portSTACK_TYPE ) 0x22; /* FSR2L. */\r
435         pxTopOfStack++;\r
436 \r
437         *pxTopOfStack = ( portSTACK_TYPE ) 0x33; /* FSR2H. */\r
438         pxTopOfStack++;\r
439 \r
440         *pxTopOfStack = ( portSTACK_TYPE ) 0x44; /* FSR0L. */\r
441         pxTopOfStack++;\r
442 \r
443         *pxTopOfStack = ( portSTACK_TYPE ) 0x55; /* FSR0H. */\r
444         pxTopOfStack++;\r
445 \r
446         *pxTopOfStack = ( portSTACK_TYPE ) 0x66; /* TABLAT. */\r
447         pxTopOfStack++;\r
448 \r
449         *pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* TBLPTRU. */\r
450         pxTopOfStack++;\r
451 \r
452         *pxTopOfStack = ( portSTACK_TYPE ) 0x88; /* TBLPTRUH. */\r
453         pxTopOfStack++;\r
454 \r
455         *pxTopOfStack = ( portSTACK_TYPE ) 0x99; /* TBLPTRUL. */\r
456         pxTopOfStack++;\r
457 \r
458         *pxTopOfStack = ( portSTACK_TYPE ) 0xaa; /* PRODH. */\r
459         pxTopOfStack++;\r
460 \r
461         *pxTopOfStack = ( portSTACK_TYPE ) 0xbb; /* PRODL. */\r
462         pxTopOfStack++;\r
463 \r
464         *pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* PCLATU. */\r
465         pxTopOfStack++;\r
466 \r
467         *pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* PCLATH. */\r
468         pxTopOfStack++;\r
469 \r
470         /* Next the .tmpdata and MATH_DATA sections. */\r
471         for( ucBlock = 0; ucBlock <= portCOMPILER_MANAGED_MEMORY_SIZE; ucBlock++ )\r
472         {\r
473                 *pxTopOfStack = ( portSTACK_TYPE ) ucBlock;\r
474                 *pxTopOfStack++;\r
475         }\r
476 \r
477         /* Store the top of the global data section. */\r
478         *pxTopOfStack = ( portSTACK_TYPE ) portCOMPILER_MANAGED_MEMORY_SIZE; /* Low. */\r
479         pxTopOfStack++;\r
480 \r
481         *pxTopOfStack = ( portSTACK_TYPE ) 0x00; /* High. */\r
482         pxTopOfStack++;\r
483 \r
484         /* The only function return address so far is the address of the \r
485         task. */\r
486         ulAddress = ( unsigned long ) pxCode;\r
487 \r
488         /* TOS low. */\r
489         *pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff );\r
490         pxTopOfStack++;\r
491         ulAddress >>= 8;\r
492 \r
493         /* TOS high. */\r
494         *pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff );\r
495         pxTopOfStack++;\r
496         ulAddress >>= 8;\r
497 \r
498         /* TOS even higher. */\r
499         *pxTopOfStack = ( portSTACK_TYPE ) ( ulAddress & ( unsigned long ) 0x00ff );\r
500         pxTopOfStack++;\r
501 \r
502         /* Store the number of return addresses on the hardware stack - so far only\r
503         the address of the task entry point. */\r
504         *pxTopOfStack = ( portSTACK_TYPE ) 1;\r
505         pxTopOfStack++;\r
506 \r
507         return pxTopOfStack;\r
508 }\r
509 /*-----------------------------------------------------------*/\r
510 \r
511 portBASE_TYPE xPortStartScheduler( void )\r
512 {\r
513         /* Setup a timer for the tick ISR is using the preemptive scheduler. */\r
514         prvSetupTimerInterrupt(); \r
515 \r
516         /* Restore the context of the first task to run. */\r
517         portRESTORE_CONTEXT();\r
518 \r
519         /* Should not get here.  Use the function name to stop compiler warnings. */\r
520         ( void ) prvLowInterrupt;\r
521         ( void ) prvTickISR;\r
522 \r
523         return pdTRUE;\r
524 }\r
525 /*-----------------------------------------------------------*/\r
526 \r
527 void vPortEndScheduler( void )\r
528 {\r
529         /* It is unlikely that the scheduler for the PIC port will get stopped\r
530         once running.  If required disable the tick interrupt here, then return \r
531         to xPortStartScheduler(). */\r
532 }\r
533 /*-----------------------------------------------------------*/\r
534 \r
535 /*\r
536  * Manual context switch.  This is similar to the tick context switch,\r
537  * but does not increment the tick count.  It must be identical to the\r
538  * tick context switch in how it stores the stack of a task.\r
539  */\r
540 void vPortYield( void )\r
541 {\r
542         /* This can get called with interrupts either enabled or disabled.  We\r
543         will save the INTCON register with the interrupt enable bits unmodified. */\r
544         portSAVE_CONTEXT( portINTERRUPTS_UNCHANGED );\r
545 \r
546         /* Switch to the highest priority task that is ready to run. */\r
547         vTaskSwitchContext();\r
548 \r
549         /* Start executing the task we have just switched to. */\r
550         portRESTORE_CONTEXT();\r
551 }\r
552 /*-----------------------------------------------------------*/\r
553 \r
554 /*\r
555  * Vector for ISR.  Nothing here must alter any registers!\r
556  */\r
557 #pragma code high_vector=0x08\r
558 static void prvLowInterrupt( void )\r
559 {\r
560         /* Was the interrupt the tick? */\r
561         if( PIR1bits.CCP1IF )\r
562         {               \r
563                 _asm\r
564                         goto prvTickISR\r
565                 _endasm\r
566         }\r
567 \r
568         /* Was the interrupt a byte being received? */\r
569         if( PIR1bits.RCIF )\r
570         {\r
571                 _asm\r
572                         goto vSerialRxISR\r
573                 _endasm\r
574         }\r
575 \r
576         /* Was the interrupt the Tx register becoming empty? */\r
577         if( PIR1bits.TXIF )\r
578         {\r
579                 if( PIE1bits.TXIE )\r
580                 {\r
581                         _asm\r
582                                 goto vSerialTxISR\r
583                         _endasm\r
584                 }\r
585         }\r
586 }\r
587 #pragma code\r
588 \r
589 /*-----------------------------------------------------------*/\r
590 \r
591 /*\r
592  * ISR for the tick.\r
593  * This increments the tick count and, if using the preemptive scheduler, \r
594  * performs a context switch.  This must be identical to the manual \r
595  * context switch in how it stores the context of a task. \r
596  */\r
597 static void prvTickISR( void )\r
598 {\r
599         /* Interrupts must have been enabled for the ISR to fire, so we have to \r
600         save the context with interrupts enabled. */\r
601         portSAVE_CONTEXT( portGLOBAL_INTERRUPT_FLAG );\r
602         PIR1bits.CCP1IF = 0;\r
603 \r
604         /* Maintain the tick count. */\r
605         if( xTaskIncrementTick() != pdFALSE )\r
606         {\r
607                 /* Switch to the highest priority task that is ready to run. */\r
608                 vTaskSwitchContext();\r
609         }\r
610 \r
611         portRESTORE_CONTEXT();\r
612 }\r
613 /*-----------------------------------------------------------*/\r
614 \r
615 /*\r
616  * Setup a timer for a regular tick.\r
617  */\r
618 static void prvSetupTimerInterrupt( void )\r
619 {\r
620 const unsigned long ulConstCompareValue = ( ( configCPU_CLOCK_HZ / portTIMER_FOSC_SCALE ) / configTICK_RATE_HZ );\r
621 unsigned long ulCompareValue;\r
622 unsigned char ucByte;\r
623 \r
624         /* Interrupts are disabled when this function is called.\r
625 \r
626         Setup CCP1 to provide the tick interrupt using a compare match on timer\r
627         1.\r
628 \r
629         Clear the time count then setup timer. */\r
630         TMR1H = ( unsigned char ) 0x00;\r
631         TMR1L = ( unsigned char ) 0x00;\r
632 \r
633         /* Set the compare match value. */\r
634         ulCompareValue = ulConstCompareValue;\r
635         CCPR1L = ( unsigned char ) ( ulCompareValue & ( unsigned long ) 0xff );\r
636         ulCompareValue >>= ( unsigned long ) 8;\r
637         CCPR1H = ( unsigned char ) ( ulCompareValue & ( unsigned long ) 0xff ); \r
638 \r
639         CCP1CONbits.CCP1M0 = portBIT_SET;       /*< Compare match mode. */\r
640         CCP1CONbits.CCP1M1 = portBIT_SET;       /*< Compare match mode. */\r
641         CCP1CONbits.CCP1M2 = portBIT_CLEAR;     /*< Compare match mode. */\r
642         CCP1CONbits.CCP1M3 = portBIT_SET;       /*< Compare match mode. */\r
643         PIE1bits.CCP1IE = portBIT_SET;          /*< Interrupt enable. */\r
644 \r
645         /* We are only going to use the global interrupt bit, so set the peripheral\r
646         bit to true. */\r
647         INTCONbits.GIEL = portBIT_SET;\r
648 \r
649         /* Provided library function for setting up the timer that will produce the\r
650         tick. */\r
651         OpenTimer1( T1_16BIT_RW & T1_SOURCE_INT & T1_PS_1_1 & T1_CCP1_T3_CCP2 );\r
652 }\r
653 \r