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hpmicro
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hpm6750evk
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start.S

start.S 1.4 KB
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  1. /*
    2. 

  2.  * Copyright (c) 2021-2023 HPMicro
    3. 

  3.  *
    4. 

  4.  * SPDX-License-Identifier: BSD-3-Clause
    5. 

  5.  *
    6. 

  6.  */
    7. 

  7.  #include <rtconfig.h>
    8. 

  8.  #include "hpm_csr_regs.h"
    9. 

  9.     .section .start, "ax"
    10. 

  10. 

  11.     .global _start
    12. 

  12.     .type _start,@function
    13. 

  13. 

  14. _start:
    15. 

  15.     /* Initialize global pointer */
    16. 

  16.     .option push
    17. 

  17.     .option norelax
    18. 

  18.     la gp, __global_pointer$
    19. 

  19.     la tp, __thread_pointer
    20. 

  20.     .option pop
    21. 

  21. 

  22.     /* Enable LMM1 clock */
    23. 

  23.     la t0, 0xF4000800
    24. 

  24.     lw t1, 0(t0)
    25. 

  25.     ori t1, t1, 0x80
    26. 

  26.     sw t1, 0(t0)
    27. 

  27. 

  28. #ifdef INIT_EXT_RAM_FOR_DATA
    29. 

  29.     la t0, _stack_in_dlm
    30. 

  30.     mv sp, t0
    31. 

  31.     call _init_ext_ram
    32. 

  32. #endif
    33. 

  33. 

  34.     /* Initialize stack pointer */
    35. 

  35.     la t0, _stack
    36. 

  36.     mv sp, t0
    37. 

  37. 

  38. #ifdef __nds_execit
    39. 

  39.     /* Initialize EXEC.IT table */
    40. 

  40.     la t0, _ITB_BASE_
    41. 

  41.     csrw uitb, t0
    42. 

  42. #endif
    43. 

  43. 

  44. #ifdef __riscv_flen
    45. 

  45.     /* Enable FPU */
    46. 

  46.     li t0, CSR_MSTATUS_FS_MASK
    47. 

  47.     csrrs t0, mstatus, t0
    48. 

  48. 

  49.     /* Initialize FCSR */
    50. 

  50.     fscsr zero
    51. 

  51. #endif
    52. 

  52.     /* Disable Vector mode */
    53. 

  53.     csrci CSR_MMISC_CTL, 2
    54. 

  54.     /* Initialize trap_entry base */
    55. 

  55.     la t0, SW_handler
    56. 

  56.     csrw mtvec, t0
    57. 

  57. 

  58. 

  59.     /* System reset handler */
    60. 

  60.     call reset_handler
    61. 

  61. 

  62.     /* Infinite loop, if returned accidently */
    63. 

  63. 1:    j 1b
    64. 

  64. 

  65.     .weak nmi_handler
    66. 

  66. nmi_handler:
    67. 

  67. 1:    j 1b
    68. 

  68. 

  69.     .global default_irq_handler
    70. 

  70.     .weak default_irq_handler
    71. 

  71.     .align 2
    72. 

  72. default_irq_handler:
    73. 

  73. 1:    j 1b
    74. 

  74. 

  75.     .macro IRQ_HANDLER irq
    76. 

  76.     .weak default_isr_\irq
    77. 

  77.     .set default_isr_\irq, default_irq_handler
    78. 

  78.     .long default_isr_\irq
    79. 

  79.     .endm
    80. 

  80. 

  81. #include "vectors.S"
    82.