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DEFINITIONS

1. boot_entry
2. vba_putc

   1 /*-
   2  * Copyright (c) 2005, Kohsuke Ohtani
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the author nor the names of any co-contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 /*
  31  * head.S - low level platform support
  32  *
  33  * This file contains the code from crt0.S which is released under
  34  * public domain by Jeff Frohwein.
  35  */
  37 /*-
  38  * Memory usage:
  39  *
  40  * 0x02000000 - 0x0203ffff : EWRAM (256K)
  41  * 0x03000000 - 0x03007fff : IWRAM (32K)
  42  * 0x04000000 - 0x040003ff : I/O Register (1K)
  43  * 0x05000000 - 0x050003ff : Palette RAM (1K)
  44  * 0x06000000 - 0x06017fff : VRAM (96K)
  45  *
  46  * Note:
  47  * 0x03007f00 - 0x03007fff is reserved by GBA BIOS.
  48  */
  50 #include <conf/config.h>
  51 #include <machine/memory.h>
  52 #include <machine/syspage.h>
  54 #define ENTRY(x) .global x; .align; x##:
  56         .section ".text","ax"
  57         .code 32
  58 /*
  59  * Loader start point
  60  */
ENTRY(boot_entry)
  62         b       rom_header_end
  64         /*
  65          * GBA ROM header
  66          */
  68         /* Nintendo Logo Character Data (8000004h) */
  69         .fill   156,1,0
  71         /* Game Title (80000A0h) */
  72         .byte   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
  73         .byte   0x00,0x00,0x00,0x00
  75         /* Game Code (80000ACh) */
  76         .byte   0x00,0x00,0x00,0x00
  78         /* Maker Code (80000B0h) */
  79         .byte   0x30,0x31
  81         /* Fixed Value (80000B2h) */
  82         .byte   0x96
  84         /* Main Unit Code (80000B3h) */
  85         .byte   0x00
  87         /* Device Type (80000B4h) */
  88         .byte   0x00
  90         /* Unused Data (7Byte) (80000B5h) */
  91         .byte   0x00,0x00,0x00,0x00,0x00,0x00,0x00
  93         /* Software Version No (80000BCh) */
  94         .byte   0x00
  96         /* Complement Check (80000BDh) */
  97         .byte   0xf0
  99         /* Checksum (80000BEh) */
 100         .byte   0x00,0x00
 102         .align
 103         .code 32
 105 rom_header_end:
 106         b       start_vector
 108         .global __boot_method, __slave_number
 110 __boot_method:
 111         .byte   0       /* boot method (0=ROM boot, 3=Multiplay boot) */
 112 __slave_number:
 113         .byte   0       /* slave # (1=slave#1, 2=slave#2, 3=slave#3) */
 115         .byte   0
 116         .byte   0
 117         .word   0
 118         .word   0
 119         .word   0
 120         .word   0
 121         .word   0
 122         .word   0
 124         .align
 125         .code 32
 126 stack_top:      .word   (BOOTSTKTOP - KERNBASE)
 128 start_vector:
 129         mov     r0, #0xd3               /* Enter SVC mode, Disable IRQ,FIQ */
 130         msr     cpsr_c, r0
 131         ldr     sp, stack_top
 133         adr     r0, thumb_mode + 1
 134         bx      r0
 135         .code 16
 136 thumb_mode:
 138 /*
 139  * Relocate the loader code
 140  */
 141         mov     r3, #0x40
 142         lsl     r3, r3, #7  /* r3 = 0x2000 (8K) */
 143         mov     r2, #3
 144         lsl     r2, r2, #24 /* r2 = 0x3000000 */
 145         lsl     r1, r3, #14 /* r1 = 0x8000000 */
 147 copy_loop:
 148         ldmia   r1!, {r0}
 149         stmia   r2!, {r0}
 150         sub     r3, r3, #4
 151         bne     copy_loop
 153         ldr     r0, =main
 154         bx      r0              /* Change to ARM mode */
 156         .code 32
 158 #if defined(DEBUG) && defined(CONFIG_DIAG_VBA)
 159 /*
 160  * Put one character to Visual Boy Advance (VBA) emulator console.
 161  *
 162  * Important:
 163  * This BIOS call is not supported by actual GBA BIOS. So, you must
 164  * disable this function when you run it on actual GBA H/W.
 165  * Otherwise, it will hang.
 166  */
 167 putbuf:
 168         .long   0
ENTRY(vba_putc)
 171         ldr     r1, =putbuf
 172         str     r0, [r1]
 173         mov     r0, r1
 174         swi     $0xff0000
 175         mov     pc, lr
 176 #endif
 178         .section .tail,"ax"
 179 dummy:
 180         .byte   0xff
 182 .end