portasm.s79 2.4 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. RSEG ICODE:CODE
  29. CODE32
  30. EXTERN vPortPreemptiveTick
  31. EXTERN vTaskSwitchContext
  32. PUBLIC vPortYieldProcessor
  33. PUBLIC vPortStartFirstTask
  34. #include "ISR_Support.h"
  35. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  36. ; Starting the first task is just a matter of restoring the context that
  37. ; was created by pxPortInitialiseStack().
  38. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  39. vPortStartFirstTask:
  40. portRESTORE_CONTEXT
  41. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  42. ; Manual context switch function. This is the SWI hander.
  43. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  44. vPortYieldProcessor:
  45. ADD LR, LR, #4 ; Add 4 to the LR to make the LR appear exactly
  46. ; as if the context was saved during and IRQ
  47. ; handler.
  48. portSAVE_CONTEXT ; Save the context of the current task...
  49. LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
  50. mov lr, pc
  51. BX R0
  52. portRESTORE_CONTEXT ; Restore the context of the selected task.
  53. END