1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
|
/*
FreeRTOS V8.2.0 - Copyright (C) 2015 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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 modification 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. !<<
***************************************************************************
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. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
/* 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. */
BaseType_t 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 UBaseType_t uxCriticalNesting = 0x80; // un-initialized
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t 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 = ( StackType_t ) *( ((StackType_t *) (&pxCode) ) + 1 );
*--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pxCode) ) + 0 );
/* Next are all the registers that form part of the task context. */
/* Y register */
*--pxTopOfStack = ( StackType_t ) 0xff;
*--pxTopOfStack = ( StackType_t ) 0xee;
/* X register */
*--pxTopOfStack = ( StackType_t ) 0xdd;
*--pxTopOfStack = ( StackType_t ) 0xcc;
/* A register contains parameter high byte. */
*--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pvParameters) ) + 0 );
/* B register contains parameter low byte. */
*--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pvParameters) ) + 1 );
/* CCR: Note that when the task starts interrupts will be enabled since
"I" bit of CCR is cleared */
*--pxTopOfStack = ( StackType_t ) 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 = ( StackType_t ) 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
}
/*-----------------------------------------------------------*/
BaseType_t 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. */
int16_t register d;
__asm ("jmp xStartSchedulerNear ; will never return": "=d"(d));
return d;
}
/*-----------------------------------------------------------*/
BaseType_t 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 ... */
if( xTaskIncrementTick() != pdFALSE )
{
/* A context switch is necessary. */
vTaskSwitchContext();
}
/* Restore the context of a task - which may be a different task
to that interrupted. */
portRESTORE_CONTEXT();
}
#else
{
xTaskIncrementTick();
}
#endif
portISR_TAIL();
}
|
