2 FreeRTOS V6.0.4 - Copyright (C) 2010 Real Time Engineers Ltd.
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25 This file is part of the FreeRTOS distribution.
27 FreeRTOS is free software; you can redistribute it and/or modify it under
28 the terms of the GNU General Public License (version 2) as published by the
29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
30 ***NOTE*** The exception to the GPL is included to allow you to distribute
31 a combined work that includes FreeRTOS without being obliged to provide the
32 source code for proprietary components outside of the FreeRTOS kernel.
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35 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
36 more details. You should have received a copy of the GNU General Public
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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54 /* Standard includes. */
57 /* Kernel includes. */
61 /* Machine includes */
62 #include <machine/counter.h>
63 #include <machine/ic.h>
64 /*-----------------------------------------------------------*/
66 /* The initial PSR has the Previous Interrupt Enabled (PIEN) flag set. */
67 #define portINITIAL_PSR ( 0x00020000 )
69 /*-----------------------------------------------------------*/
72 * Perform any hardware configuration necessary to generate the tick interrupt.
74 static void prvSetupTimerInterrupt( void );
75 /*-----------------------------------------------------------*/
77 portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE * pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
79 /* For the time being, mimic the stack when using the
80 __attribute__((interrupt)) plus the extra caller saved registers. */
81 This leaves a buffer of two works unused. */
85 pxTopOfStack[ 16 ] = ( portSTACK_TYPE )pxCode;
88 pxTopOfStack[ 15 ] = portINITIAL_PSR;
90 /* R14 and R15 aka FuncSP and LR, respectively */
91 pxTopOfStack[ 14 ] = 0x00000000;
92 pxTopOfStack[ 13 ] = ( portSTACK_TYPE )( pxTopOfStack + 17 );
95 pxTopOfStack[ 12 ] = 0x07070707;
96 pxTopOfStack[ 11 ] = 0x06060606;
97 pxTopOfStack[ 10 ] = 0x05050505;
98 pxTopOfStack[ 9 ] = 0x04040404;
99 pxTopOfStack[ 8 ] = 0x03030303;
100 pxTopOfStack[ 7 ] = ( portSTACK_TYPE )pvParameters;
102 /* Set the Interrupt Priority on Task entry. */
103 pxTopOfStack[ 6 ] = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
106 pxTopOfStack[ 5 ] = 0x0D0D0D0D;
107 pxTopOfStack[ 4 ] = 0x0C0C0C0C;
108 pxTopOfStack[ 3 ] = 0x0B0B0B0B;
109 pxTopOfStack[ 2 ] = 0x0A0A0A0A;
110 pxTopOfStack[ 1 ] = 0x09090909;
111 pxTopOfStack[ 0 ] = 0x08080808;
115 /*-----------------------------------------------------------*/
117 portBASE_TYPE xPortStartScheduler( void )
119 /* Set-up the timer interrupt. */
120 prvSetupTimerInterrupt();
122 /* Enable the TRAP yield. */
123 irq[ portIRQ_TRAP_YIELD ].ien = 1;
124 irq[ portIRQ_TRAP_YIELD ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
126 /* Integrated Interrupt Controller: Enable all interrupts. */
129 /* Restore callee saved registers. */
130 portRESTORE_CONTEXT();
132 /* Mimic an ISR epilogue to start the task executing. */
134 "ldd r6, [r1]+0x20 \n" \
137 "ldd r14, [r1]+0x18 \n" \
138 "ldq r4, [r1]+0x8 \n" \
144 /* Should not get here. */
147 /*-----------------------------------------------------------*/
149 static void prvSetupTimerInterrupt( void )
151 /* Enable timer interrupts */
152 counter1->reload = ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) - 1;
153 counter1->value = counter1->reload;
156 /* Set the IRQ Handler priority and enable it. */
157 irq[ IRQ_COUNTER1 ].ien = 1;
158 irq[ IRQ_COUNTER1 ].ipl = portKERNEL_INTERRUPT_PRIORITY_LEVEL;
160 /*-----------------------------------------------------------*/
162 void interrupt_handler( portIRQ_TRAP_YIELD )
164 /* Save remaining registers. */
167 vTaskSwitchContext();
169 /* Restore the first lot of registers, the remains will be restored when
170 this function exits. */
171 portRESTORE_CONTEXT();
173 /*-----------------------------------------------------------*/
175 /* Timer tick interrupt handler */
176 void interrupt_handler( IRQ_COUNTER1 )
180 vTaskIncrementTick();
182 #if configUSE_PREEMPTION == 1
183 vTaskSwitchContext();
186 /* Clear the Tick Interrupt. */
187 counter1->expired = 0;
189 portRESTORE_CONTEXT();
191 /*-----------------------------------------------------------*/
193 void vPortEndScheduler( void )
195 /* Nothing to do. Unlikely to want to end. */
197 /*-----------------------------------------------------------*/