i386/linux/linux-2.3.21/arch/arm/boot/compressed/head-nexuspci.S

   1 /*
   2  * linux/arch/arm/boot/compressed/head-nexuspci.S
   3  *
   4  * Copyright (C) 1996, 1997, 1998 Philip Blundell
   5  *
   6  * NexusPCI is unusual because we don't have a bootloader -- the kernel is
   7  * run directly out of ROM at the moment.  Maybe this will change one day and
   8  * then this file can go away.
   9  *
  10  */
  11
  12                 .text
  13
  14 .globl  _start
  15 _start:         b       reset
  16                 b       undefined
  17                 b       undefined
  18                 b       undefined
  19                 b       undefined
  20                 b       undefined
  21                 b       undefined
  22                 b       undefined
  23                 b       go_uncompress
  24
  25 reset:          mov     r2, #0x20000000                 @ LED off
  26                 mov     r1, #0x1a
  27                 str     r1, [r2]
  28
  29                 mov     r2, #0x10000000                 @ SCC init
  30
  31                 mov     r1, #42
  32                 strb    r1, [r2, #8]
  33
  34                 mov     r1, #48
  35                 strb    r1, [r2, #8]
  36
  37                 mov     r1, #16
  38                 strb    r1, [r2, #8]
  39
  40                 mov     r1, #0x93
  41                 strb    r1, [r2, #0]
  42                 mov     r1, #0x17
  43                 strb    r1, [r2, #0]
  44
  45                 mov     r1, #0xbb
  46                 strb    r1, [r2, #0x4]
  47
  48                 mov     r1, #0x78
  49                 strb    r1, [r2, #0x10]
  50
  51                 mov     r1, #160
  52                 strb    r1, [r2, #0x8]
  53
  54                 mov     r1, #5
  55                 strb    r1, [r2, #0x8]
  56
  57                 ldr     r2, =_start
  58                 ldr     r3, =_edata
  59                 mov     r8, r2
  60                 mov     r0, #0
  61 1:
  62                 ldmia   r0!, {r4, r5, r6, r7}
  63                 stmia   r2!, {r4, r5, r6, r7}
  64                 cmp     r2, r3
  65                 ble     1b
  66
  67                 ldr     r3, =_edata
  68                 ldr     r1, =_end
  69                 mov     r2, #0
  70 1:
  71                 strb    r2, [r3]
  72                 cmp     r3, r1
  73                 beq     2f
  74                 add     r3, r3, #1
  75                 b       1b
  76 2:
  77                 add     pc, r8, #0x20
  78
  79 undefined:      ldr     r4, =undef_msg
  80 1:              ldrb    r0, [r4], #1
  81                 movs    r0, r0
  82 2:              beq     2b
  83                 bl      _ll_write_char
  84                 b       1b
  85
  86 undef_msg:      .ascii  "Undefined instruction (or other problem)\000"
  87                 .align  4
  88
  89 /*
  90  * Uncompress the kernel
  91  */
  92 go_uncompress:
  93                 mov     r0, #0x40000000
  94                 ldr     sp, =user_stack
  95                 add     sp, sp, #4096
  96                 bl      decompress_kernel
  97
  98                 mov     r2, #0x40000000
  99                 mov     r0, #0
 100                 mov     r1, #3
 101                 add     pc, r2, #0x20           @ call via EXEC entry