portasm.s79 2.3 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 vTaskSwitchContext
  31. PUBLIC vPortYieldProcessor
  32. PUBLIC vPortStartFirstTask
  33. #include "ISR_Support.h"
  34. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  35. ; Starting the first task is just a matter of restoring the context that
  36. ; was created by pxPortInitialiseStack().
  37. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  38. vPortStartFirstTask:
  39. portRESTORE_CONTEXT
  40. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  41. ; Manual context switch function. This is the SWI hander.
  42. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  43. vPortYieldProcessor:
  44. ADD LR, LR, #4 ; Add 4 to the LR to make the LR appear exactly
  45. ; as if the context was saved during and IRQ
  46. ; handler.
  47. portSAVE_CONTEXT ; Save the context of the current task...
  48. LDR R0, =vTaskSwitchContext ; before selecting the next task to execute.
  49. MOV lr, pc
  50. BX R0
  51. portRESTORE_CONTEXT ; Restore the context of the selected task.
  52. END