2 * FreeRTOS Kernel V10.3.0
\r
3 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
\r
5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
\r
6 * this software and associated documentation files (the "Software"), to deal in
\r
7 * the Software without restriction, including without limitation the rights to
\r
8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
\r
9 * the Software, and to permit persons to whom the Software is furnished to do so,
\r
10 * subject to the following conditions:
\r
12 * The above copyright notice and this permission notice shall be included in all
\r
13 * copies or substantial portions of the Software.
\r
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
\r
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
\r
17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
\r
18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
\r
19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
\r
20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\r
22 * http://www.FreeRTOS.org
\r
23 * http://aws.amazon.com/freertos
\r
25 * 1 tab == 4 spaces!
\r
28 #include "FreeRTOSConfig.h"
\r
29 #include "data_model.h"
\r
31 IMPORT xTaskIncrementTick
\r
32 IMPORT vTaskSwitchContext
\r
33 IMPORT vPortSetupTimerInterrupt
\r
35 IMPORT usCriticalNesting
\r
39 EXPORT xPortStartScheduler
\r
41 portSAVE_CONTEXT macro
\r
43 /* Save the remaining registers. */
\r
45 mov.w &usCriticalNesting, r14
\r
47 mov_x &pxCurrentTCB, r12
\r
50 /*-----------------------------------------------------------*/
\r
52 portRESTORE_CONTEXT macro
\r
54 mov_x &pxCurrentTCB, r12
\r
57 mov.w r15, &usCriticalNesting
\r
64 /*-----------------------------------------------------------*/
\r
68 * The RTOS tick ISR.
\r
70 * If the cooperative scheduler is in use this simply increments the tick
\r
73 * If the preemptive scheduler is in use a context switch can also occur.
\r
81 /* The sr is not saved in portSAVE_CONTEXT() because vPortYield() needs
\r
82 to save it manually before it gets modified (interrupts get disabled).
\r
83 Entering through this interrupt means the SR is already on the stack, but
\r
84 this keeps the stack frames identical. */
\r
88 calla #xTaskIncrementTick
\r
90 jeq SkipContextSwitch
\r
91 calla #vTaskSwitchContext
\r
94 /*-----------------------------------------------------------*/
\r
97 * Manual context switch called by the portYIELD() macro.
\r
103 /* The sr needs saving before it is modified. */
\r
106 /* Now the SR is stacked interrupts can be disabled. */
\r
110 /* Save the context of the current task. */
\r
113 /* Select the next task to run. */
\r
114 calla #vTaskSwitchContext
\r
116 /* Restore the context of the new task. */
\r
117 portRESTORE_CONTEXT
\r
118 /*-----------------------------------------------------------*/
\r
122 * Start off the scheduler by initialising the RTOS tick timer, then restoring
\r
123 * the context of the first task.
\r
127 xPortStartScheduler:
\r
129 /* Setup the hardware to generate the tick. Interrupts are disabled
\r
130 when this function is called. */
\r
131 calla #vPortSetupTimerInterrupt
\r
133 /* Restore the context of the first task that is going to run. */
\r
134 portRESTORE_CONTEXT
\r
135 /*-----------------------------------------------------------*/
\r