testing/examples/ledtest-imx27ads/crt0.S

   1 /* Sample initialization file */
   2
   3         .extern main
   4         .extern exit
   5
   6 /* .text is used instead of .section .text so it works with arm-aout too.  */
   7         .text
   8         .code 32
   9         .align  0
  10
  11         .global _mainCRTStartup
  12         .global _start
  13         .global start
  14 start:
  15 _start:
  16 _mainCRTStartup:
  17
  18 /* Start by setting up a stack */
  19         /*  Set up the stack pointer to end of bss */
  20         ldr     r3, .LC2
  21         mov     sp, r3
  22
  23         sub     sl, sp, #512    /* Still assumes 512 bytes below sl */
  24
  25         mov     a2, #0          /* Second arg: fill value */
  26         mov     fp, a2          /* Null frame pointer */
  27         mov     r7, a2          /* Null frame pointer for Thumb */
  28
  29         ldr     a1, .LC1        /* First arg: start of memory block */
  30         ldr     a3, .LC2        /* Second arg: end of memory block */
  31         sub     a3, a3, a1      /* Third arg: length of block */
  32
  33         mov     r0, #0          /*  no arguments  */
  34         mov     r1, #0          /*  no argv either */
  35
  36         bl      main
  37         bl      exit            /* Should not return */
  38
  39         /* For Thumb, constants must be after the code since only
  40         positive offsets are supported for PC relative addresses. */
  41
  42         .align 0
  43 .LC1:
  44         .word   __bss_start__
  45 .LC2:
  46         .word   __bss_end__
  47