portext.s43 2.9 KB

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  1. /*
  2. * FreeRTOS Kernel V10.4.6
  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 "FreeRTOSConfig.h"
  29. #include "portasm.h"
  30. IMPORT xTaskIncrementTick
  31. IMPORT vTaskSwitchContext
  32. IMPORT vPortSetupTimerInterrupt
  33. EXPORT vTickISR
  34. EXPORT vPortYield
  35. EXPORT xPortStartScheduler
  36. RSEG CODE
  37. /*
  38. * The RTOS tick ISR.
  39. *
  40. * If the cooperative scheduler is in use this simply increments the tick
  41. * count.
  42. *
  43. * If the preemptive scheduler is in use a context switch can also occur.
  44. */
  45. vTickISR:
  46. portSAVE_CONTEXT
  47. call #xTaskIncrementTick
  48. cmp.w #0x0, R12
  49. jeq SkipContextSwitch
  50. call #vTaskSwitchContext
  51. SkipContextSwitch:
  52. portRESTORE_CONTEXT
  53. /*-----------------------------------------------------------*/
  54. /*
  55. * Manual context switch called by the portYIELD() macro.
  56. */
  57. vPortYield:
  58. /* Mimic an interrupt by pushing the SR. */
  59. push SR
  60. /* Now the SR is stacked we can disable interrupts. */
  61. dint
  62. /* Save the context of the current task. */
  63. portSAVE_CONTEXT
  64. /* Switch to the highest priority task that is ready to run. */
  65. call #vTaskSwitchContext
  66. /* Restore the context of the new task. */
  67. portRESTORE_CONTEXT
  68. /*-----------------------------------------------------------*/
  69. /*
  70. * Start off the scheduler by initialising the RTOS tick timer, then restoring
  71. * the context of the first task.
  72. */
  73. xPortStartScheduler:
  74. /* Setup the hardware to generate the tick. Interrupts are disabled
  75. when this function is called. */
  76. call #vPortSetupTimerInterrupt
  77. /* Restore the context of the first task that is going to run. */
  78. portRESTORE_CONTEXT
  79. /*-----------------------------------------------------------*/
  80. /* Install vTickISR as the timer A0 interrupt. */
  81. ASEG
  82. ORG 0xFFE0 + TIMERA0_VECTOR
  83. _vTickISR_: DC16 vTickISR
  84. END