crt0.S 2.8 KB

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  1. /* Startup code for SH & ELF.
  2. Copyright (C) 1999 Free Software Foundation, Inc.
  3. Copyright (C) 2001 Hewlett-Packard Australia
  4. Copyright (C) 2002 Stefan Allius
  5. This program is free software; you can redistribute it and/or modify it under
  6. the terms of the GNU Library General Public License as published by the Free
  7. Software Foundation; either version 2 of the License, or (at your option) any
  8. later version.
  9. This program is distributed in the hope that it will be useful, but WITHOUT
  10. ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11. FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more
  12. details.
  13. You should have received a copy of the GNU Library General Public License
  14. along with this program; if not, write to the Free Software Foundation, Inc.,
  15. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16. */
  17. /* This is the canonical entry point, usually the first thing in the text
  18. segment.
  19. At this entry point, most registers' values are unspecified, except:
  20. sp The stack contains the arguments and environment:
  21. 0(sp) argc
  22. 4(sp) argv[0]
  23. ...
  24. (4*argc)(sp) NULL
  25. (4*(argc+1))(sp) envp[0]
  26. ...
  27. NULL
  28. */
  29. #include <features.h>
  30. .file "crt0.S"
  31. .text
  32. .globl _start
  33. .type _start,@function
  34. .type main,@function
  35. .size _start,_start_end - _start
  36. _start:
  37. /* Clear the frame pointer since this is the outermost frame. */
  38. mov #0, r14
  39. /* Pop argc off the stack and save a pointer to argv */
  40. mov.l @r15+,r4
  41. mov r15, r5
  42. #if defined L_crt0 || ! defined __UCLIBC_CTOR_DTOR__
  43. /*
  44. * Setup the value for the environment pointer:
  45. * r6 = (argc + 1) * 4
  46. * r6 += argv (in delay slot)
  47. */
  48. mov r4,r6
  49. add #1,r6
  50. shll2 r6
  51. /* jump to __uClibc_main (argc, argv, envp) */
  52. mov.l L_main, r0
  53. jsr @r0
  54. add r5, r6 /* delay slot */
  55. /* We should not get here. */
  56. mov.l L_abort, r0
  57. jmp @r0
  58. nop
  59. _start_end:
  60. .align 2
  61. L_main:
  62. .long __uClibc_main /* in libuClibc.*.so */
  63. #else /* L_crt1 && __UCLIBC_CTOR_DTOR__ */
  64. /* Push the finip argument to __uClibc_start_main() onto the stack */
  65. mov.l L_fini,r6
  66. mov.l r6,@-r15
  67. /* Setup the value for the initp argument */
  68. mov.l L_init, r7
  69. /*
  70. * Setup the value for the environment pointer:
  71. * r6 = (argc + 1) * 4
  72. * r6 += argv (in delay slot)
  73. */
  74. mov r4,r6
  75. add #1,r6
  76. shll2 r6
  77. /* jump to __uClibc_start_main (argc, argv, envp, app_init, app_fini) */
  78. mov.l L_main, r0
  79. jsr @r0
  80. add r5, r6 /* delay slot */
  81. /* We should not get here. */
  82. mov.l L_abort, r0
  83. jmp @r0
  84. nop
  85. _start_end:
  86. .align 2
  87. L_main:
  88. .long __uClibc_start_main /* in libuClibc.*.so */
  89. .weak _init
  90. .type _init,@function
  91. _init:
  92. rts
  93. nop
  94. .Lfe1:
  95. .size _init,.Lfe1-_init
  96. .weak _fini
  97. .set _fini,_init
  98. L_init:
  99. .long _init
  100. L_fini:
  101. .long _fini
  102. #endif
  103. L_abort:
  104. .long abort