2 FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.
\r
4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
\r
6 ***************************************************************************
\r
8 * FreeRTOS provides completely free yet professionally developed, *
\r
9 * robust, strictly quality controlled, supported, and cross *
\r
10 * platform software that has become a de facto standard. *
\r
12 * Help yourself get started quickly and support the FreeRTOS *
\r
13 * project by purchasing a FreeRTOS tutorial book, reference *
\r
14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
\r
18 ***************************************************************************
\r
20 This file is part of the FreeRTOS distribution.
\r
22 FreeRTOS is free software; you can redistribute it and/or modify it under
\r
23 the terms of the GNU General Public License (version 2) as published by the
\r
24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
\r
26 >>! NOTE: The modification to the GPL is included to allow you to distribute
\r
27 >>! a combined work that includes FreeRTOS without being obliged to provide
\r
28 >>! the source code for proprietary components outside of the FreeRTOS
\r
31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
\r
32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
\r
33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
\r
34 link: http://www.freertos.org/a00114.html
\r
38 ***************************************************************************
\r
40 * Having a problem? Start by reading the FAQ "My application does *
\r
41 * not run, what could be wrong?" *
\r
43 * http://www.FreeRTOS.org/FAQHelp.html *
\r
45 ***************************************************************************
\r
47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
\r
48 license and Real Time Engineers Ltd. contact details.
\r
50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
\r
51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
\r
52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
\r
54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
\r
55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
\r
56 licenses offer ticketed support, indemnification and middleware.
\r
58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
\r
59 engineered and independently SIL3 certified version for use in safety and
\r
60 mission critical applications that require provable dependability.
\r
66 /*-----------------------------------------------------------
\r
67 * Implementation of functions defined in portable.h for the Tern EE 186
\r
69 *----------------------------------------------------------*/
\r
71 /* Library includes. */
\r
72 #include <embedded.h>
\r
75 /* Scheduler includes. */
\r
76 #include "FreeRTOS.h"
\r
78 #include "portasm.h"
\r
80 /* The timer increments every four clocks, hence the divide by 4. */
\r
81 #define portPRESCALE_VALUE ( 16 )
\r
82 #define portTIMER_COMPARE ( configCPU_CLOCK_HZ / ( configTICK_RATE_HZ * 4UL ) )
\r
84 /* From the RDC data sheet. */
\r
85 #define portENABLE_TIMER_AND_INTERRUPT ( unsigned short ) 0xe00b
\r
86 #define portENABLE_TIMER ( unsigned short ) 0xC001
\r
88 /* Interrupt control. */
\r
89 #define portEIO_REGISTER 0xff22
\r
90 #define portCLEAR_INTERRUPT 0x0008
\r
92 /* Setup the hardware to generate the required tick frequency. */
\r
93 static void prvSetupTimerInterrupt( void );
\r
95 /* The ISR used depends on whether the preemptive or cooperative scheduler
\r
97 #if( configUSE_PREEMPTION == 1 )
\r
98 /* Tick service routine used by the scheduler when preemptive scheduling is
\r
100 static void __interrupt __far prvPreemptiveTick( void );
\r
102 /* Tick service routine used by the scheduler when cooperative scheduling is
\r
104 static void __interrupt __far prvNonPreemptiveTick( void );
\r
107 /* Trap routine used by taskYIELD() to manually cause a context switch. */
\r
108 static void __interrupt __far prvYieldProcessor( void );
\r
110 /*-----------------------------------------------------------*/
\r
111 /* See header file for description. */
\r
112 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
\r
114 portSTACK_TYPE DS_Reg = 0;
\r
116 /* We need the true data segment. */
\r
117 __asm{ MOV DS_Reg, DS };
\r
119 /* Place a few bytes of known values on the bottom of the stack.
\r
120 This is just useful for debugging. */
\r
122 *pxTopOfStack = 0x1111;
\r
124 *pxTopOfStack = 0x2222;
\r
126 *pxTopOfStack = 0x3333;
\r
129 /* We are going to start the scheduler using a return from interrupt
\r
130 instruction to load the program counter, so first there would be the
\r
131 function call with parameters preamble. */
\r
133 *pxTopOfStack = FP_OFF( pvParameters );
\r
135 *pxTopOfStack = FP_OFF( pxCode );
\r
138 /* Next the status register and interrupt return address. */
\r
139 *pxTopOfStack = portINITIAL_SW;
\r
141 *pxTopOfStack = FP_SEG( pxCode );
\r
143 *pxTopOfStack = FP_OFF( pxCode );
\r
146 /* The remaining registers would be pushed on the stack by our context
\r
147 switch function. These are loaded with values simply to make debugging
\r
149 *pxTopOfStack = ( portSTACK_TYPE ) 0xAAAA; /* AX */
\r
151 *pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BX */
\r
153 *pxTopOfStack = ( portSTACK_TYPE ) 0xCCCC; /* CX */
\r
155 *pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DX */
\r
157 *pxTopOfStack = ( portSTACK_TYPE ) 0xEEEE; /* ES */
\r
160 *pxTopOfStack = DS_Reg; /* DS */
\r
162 *pxTopOfStack = ( portSTACK_TYPE ) 0x0123; /* SI */
\r
164 *pxTopOfStack = ( portSTACK_TYPE ) 0xDDDD; /* DI */
\r
166 *pxTopOfStack = ( portSTACK_TYPE ) 0xBBBB; /* BP */
\r
168 return pxTopOfStack;
\r
170 /*-----------------------------------------------------------*/
\r
172 portBASE_TYPE xPortStartScheduler( void )
\r
174 /* This is called with interrupts already disabled. */
\r
176 /* Put our manual switch (yield) function on a known
\r
178 setvect( portSWITCH_INT_NUMBER, prvYieldProcessor );
\r
180 /* Setup the tick interrupt. */
\r
181 prvSetupTimerInterrupt();
\r
183 /* Kick off the scheduler by setting up the context of the first task. */
\r
184 portFIRST_CONTEXT();
\r
186 /* Should not get here! */
\r
189 /*-----------------------------------------------------------*/
\r
191 /* The ISR used depends on whether the preemptive or cooperative scheduler
\r
193 #if( configUSE_PREEMPTION == 1 )
\r
194 static void __interrupt __far prvPreemptiveTick( void )
\r
196 /* Get the scheduler to update the task states following the tick. */
\r
197 if( xTaskIncrementTick() != pdFALSE )
\r
199 /* Switch in the context of the next task to be run. */
\r
200 portEND_SWITCHING_ISR();
\r
203 /* Reset interrupt. */
\r
204 outport( portEIO_REGISTER, portCLEAR_INTERRUPT );
\r
207 static void __interrupt __far prvNonPreemptiveTick( void )
\r
209 /* Same as preemptive tick, but the cooperative scheduler is being used
\r
210 so we don't have to switch in the context of the next task. */
\r
211 xTaskIncrementTick();
\r
213 /* Reset interrupt. */
\r
214 outport( portEIO_REGISTER, portCLEAR_INTERRUPT );
\r
217 /*-----------------------------------------------------------*/
\r
219 static void __interrupt __far prvYieldProcessor( void )
\r
221 /* Switch in the context of the next task to be run. */
\r
222 portEND_SWITCHING_ISR();
\r
224 /*-----------------------------------------------------------*/
\r
226 void vPortEndScheduler( void )
\r
228 /* Not implemented. */
\r
230 /*-----------------------------------------------------------*/
\r
232 static void prvSetupTimerInterrupt( void )
\r
234 const unsigned long ulCompareValue = portTIMER_COMPARE;
\r
235 unsigned short usTimerCompare;
\r
237 usTimerCompare = ( unsigned short ) ( ulCompareValue >> 4 );
\r
238 t2_init( portENABLE_TIMER, portPRESCALE_VALUE, NULL );
\r
240 #if( configUSE_PREEMPTION == 1 )
\r
241 /* Tick service routine used by the scheduler when preemptive scheduling is
\r
243 t1_init( portENABLE_TIMER_AND_INTERRUPT, usTimerCompare, usTimerCompare, prvPreemptiveTick );
\r
245 /* Tick service routine used by the scheduler when cooperative scheduling is
\r
247 t1_init( portENABLE_TIMER_AND_INTERRUPT, usTimerCompare, usTimerCompare, prvNonPreemptiveTick );
\r