1;/*
2; * FreeRTOS Kernel V11.1.0
3; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4; *
5; * SPDX-License-Identifier: MIT
6; *
7; * Permission is hereby granted, free of charge, to any person obtaining a copy of
8; * this software and associated documentation files (the "Software"), to deal in
9; * the Software without restriction, including without limitation the rights to
10; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
11; * the Software, and to permit persons to whom the Software is furnished to do so,
12; * subject to the following conditions:
13; *
14; * The above copyright notice and this permission notice shall be included in all
15; * copies or substantial portions of the Software.
16; *
17; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
19; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
20; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
21; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23; *
24; * https://www.FreeRTOS.org
25; * https://github.com/FreeRTOS
26; *
27; */
28
29        RSEG ICODE:CODE
30        CODE32
31
32    EXTERN vTaskSwitchContext
33    EXTERN vPortPreemptiveTick
34
35    PUBLIC vPortPreemptiveTickEntry
36    PUBLIC vPortYieldProcessor
37    PUBLIC vPortStartFirstTask
38
39#include "FreeRTOSConfig.h"
40#include "ISR_Support.h"
41
42;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
43; Starting the first task is just a matter of restoring the context that
44; was created by pxPortInitialiseStack().
45;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
46vPortStartFirstTask:
47    portRESTORE_CONTEXT
48
49;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
50; Manual context switch function.  This is the SWI hander.
51;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
52vPortYieldProcessor:
53    ADD     LR, LR, #4          ; Add 4 to the LR to make the LR appear exactly
54                                ; as if the context was saved during and IRQ
55                                ; handler.
56
57    portSAVE_CONTEXT            ; Save the context of the current task...
58    LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
59    mov     lr, pc
60    BX R0
61    portRESTORE_CONTEXT         ; Restore the context of the selected task.
62
63;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
64; Preemptive context switch function.  This will only ever get installed if
65; portUSE_PREEMPTION is set to 1 in portmacro.h.
66;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
67vPortPreemptiveTickEntry:
68#if configUSE_PREEMPTION == 1
69    portSAVE_CONTEXT            ; Save the context of the current task...
70    LDR R0, =vPortPreemptiveTick; before selecting the next task to execute.
71    mov     lr, pc
72    BX R0
73    portRESTORE_CONTEXT         ; Restore the context of the selected task.
74#endif
75
76    END
77