crossarm-lpc210x-crt0.s

   1
   2                 .set    SYSTEM_MODE,            0x1F
   3                 .set    UNDEFINED_MODE,         0x1B
   4                 .set    ABORT_MODE,             0x17
   5                 .set    SUPERVISOR_MODE,        0x13
   6                 .set    IRQ_MODE,               0x12
   7                 .set    FIQ_MODE,               0x11
   8                 .set    USER_MODE,              0x10
   9
  10                 .text
  11                 .arm
  12                 .org    0
  13                 .align  0
  14
  15 # exception vectors
  16
  17                 b       reset_handler
  18                 ldr     pc, undefined_instruction_handler_addr
  19                 ldr     pc, software_interrupt_handler_addr
  20                 ldr     pc, prefetch_abort_handler_addr
  21                 ldr     pc, data_abort_handler_addr
  22                 ldr     pc, endless_loop        /* ARM-reserved vector */
  23                 ldr     pc, irq_handler_addr
  24                 ldr     pc, fiq_handler_addr
  25
  26 undefined_instruction_handler_addr:     .long   undefined_instruction_handler
  27 software_interrupt_handler_addr:        .long   software_interrupt_handler
  28 prefetch_abort_handler_addr:            .long   prefetch_abort_handler
  29 data_abort_handler_addr:                .long   data_abort_handler
  30 irq_handler_addr:                       .long   irq_handler
  31 fiq_handler_addr:                       .long   fiq_handler
  32
  33 .global reset_handler
  34 reset_handler:
  35
  36                 msr     cpsr_c, #UNDEFINED_MODE
  37                 ldr     sp, =__UNDEFINED_SP__
  38                 msr     cpsr_c, #ABORT_MODE
  39                 ldr     sp, =__ABORT_SP__
  40                 msr     cpsr_c, #IRQ_MODE
  41                 ldr     sp, =__IRQ_SP__
  42                 msr     cpsr_c, #FIQ_MODE
  43                 ldr     sp, =__FIQ_SP__
  44                 msr     cpsr_c, #SUPERVISOR_MODE
  45                 ldr     sp, =__SUPERVISOR_SP__
  46
  47 # setup a default stack limit (when compiled with "-mapcs-stack-check").
  48 #               sub     sl, sp, #__USER_STACK_SIZE__
  49
  50 # relocate .data(rw) section (copy from FLASH to RAM).
  51
  52                 ldr     r1, =__text_end__
  53                 ldr     r2, =__data_start__
  54                 ldr     r3, =__data_end__
  55
  56 reset_handler_L01:
  57
  58                 cmp     r2, r3
  59                 ldrlo   r0, [r1], #4
  60                 strlo   r0, [r2], #4
  61                 blo     reset_handler_L01
  62
  63 # clear .bss(rw) section.
  64
  65                 mov     r0, #0
  66                 ldr     r1, =__bss_start__
  67                 ldr     r2, =__bss_end__
  68
  69 reset_handler_L02:
  70
  71                 cmp     r1, r2
  72                 strlo   r0, [r1], #4
  73                 blo     reset_handler_L02
  74
  75 # set up arguments to main() and call.
  76
  77                 mov     r0, #0
  78                 mov     r1, #0
  79                 bl      main
  80
  81 .global endless_loop
  82 endless_loop:
  83                 b       endless_loop
  84
  85                 .end