xref: /Kernel-v10.6.2/portable/IAR/MSP430X/portext.s43 (revision ef7b253b56c9788077f5ecd6c9deb4021923d646) 
1/*
2 * FreeRTOS Kernel V10.6.2
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#include "msp430.h"
29#include "FreeRTOSConfig.h"
30#include "data_model.h"
31
32    IMPORT xTaskIncrementTick
33    IMPORT vTaskSwitchContext
34    IMPORT vPortSetupTimerInterrupt
35    IMPORT pxCurrentTCB
36    IMPORT usCriticalNesting
37
38    EXPORT vPortTickISR
39    EXPORT vPortYield
40    EXPORT xPortStartScheduler
41
42portSAVE_CONTEXT macro
43
44    /* Save the remaining registers. */
45    pushm_x #12, r15
46    mov.w   &usCriticalNesting, r14
47    push_x r14
48    mov_x   &pxCurrentTCB, r12
49    mov_x   sp, 0( r12 )
50    endm
51/*-----------------------------------------------------------*/
52
53portRESTORE_CONTEXT macro
54
55    mov_x   &pxCurrentTCB, r12
56    mov_x   @r12, sp
57    pop_x   r15
58    mov.w   r15, &usCriticalNesting
59    popm_x  #12, r15
60    nop
61    pop.w   sr
62    nop
63    reta
64    endm
65/*-----------------------------------------------------------*/
66
67
68/*
69 * The RTOS tick ISR.
70 *
71 * If the cooperative scheduler is in use this simply increments the tick
72 * count.
73 *
74 * If the preemptive scheduler is in use a context switch can also occur.
75 */
76
77    RSEG CODE
78    EVEN
79
80vPortTickISR:
81
82    /* The sr is not saved in portSAVE_CONTEXT() because vPortYield() needs
83    to save it manually before it gets modified (interrupts get disabled).
84    Entering through this interrupt means the SR is already on the stack, but
85    this keeps the stack frames identical. */
86    push.w sr
87    portSAVE_CONTEXT
88
89    calla   #xTaskIncrementTick
90    cmp.w   #0x0, R12
91    jeq     SkipContextSwitch
92    calla   #vTaskSwitchContext
93SkipContextSwitch:
94    portRESTORE_CONTEXT
95/*-----------------------------------------------------------*/
96
97/*
98 * Manual context switch called by the portYIELD() macro.
99 */
100    EVEN
101
102vPortYield:
103
104    /* The sr needs saving before it is modified. */
105    push.w  sr
106
107    /* Now the SR is stacked interrupts can be disabled. */
108    dint
109    nop
110
111    /* Save the context of the current task. */
112    portSAVE_CONTEXT
113
114    /* Select the next task to run. */
115    calla   #vTaskSwitchContext
116
117    /* Restore the context of the new task. */
118    portRESTORE_CONTEXT
119/*-----------------------------------------------------------*/
120
121
122/*
123 * Start off the scheduler by initialising the RTOS tick timer, then restoring
124 * the context of the first task.
125 */
126    EVEN
127
128xPortStartScheduler:
129
130    /* Setup the hardware to generate the tick.  Interrupts are disabled
131    when this function is called. */
132    calla   #vPortSetupTimerInterrupt
133
134    /* Restore the context of the first task that is going to run. */
135    portRESTORE_CONTEXT
136/*-----------------------------------------------------------*/
137
138    END
139