firmware/decompressor/decompressor.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 by Jens Arnold
  11  *
  12  * Self-extracting firmware loader to work around the 200KB size limit
  13  * for archos player and recorder v1
  14  * Decompresses a built-in UCL-compressed image (method 2e) and executes it.
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License
  18  * as published by the Free Software Foundation; either version 2
  19  * of the License, or (at your option) any later version.
  20  *
  21  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  22  * KIND, either express or implied.
  23  *
  24  ****************************************************************************/
  25
  26 #include "uclimage.h"
  27
  28 #define ICODE_ATTR __attribute__ ((section (".icode")))
  29
  30 /* Symbols defined in the linker script */
  31 extern char iramcopy[], iramstart[], iramend[];
  32 extern char stackend[];
  33 extern char loadaddress[], dramend[];
  34
  35 /* Prototypes */
  36 extern void start(void);
  37
  38 void main(void) ICODE_ATTR;
  39 int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
  40                            unsigned long *dst_len) ICODE_ATTR;
  41
  42 /* Vector table */
  43 void (*vbr[]) (void) __attribute__ ((section (".vectors"))) =
  44 {
  45     start, (void *)stackend,
  46     start, (void *)stackend,
  47             0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  48     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  49 };
  50
  51 /** All subsequent functions are executed from IRAM **/
  52
  53 #define ALIGNED_IMG_SIZE ((sizeof(image) + 3) & ~3)
  54 /* This will never return */
  55 void main(void)
  56 {
  57     unsigned long dst_len; /* dummy */
  58     unsigned long *src = (unsigned long *)image;
  59     unsigned long *dst = (unsigned long *)(dramend - ALIGNED_IMG_SIZE);
  60
  61     do
  62         *dst++ = *src++;
  63     while (dst < (unsigned long *)dramend);
  64
  65     ucl_nrv2e_decompress_8(dramend - ALIGNED_IMG_SIZE, loadaddress, &dst_len);
  66
  67     asm(
  68         "mov.l   @%0+,r0     \n"
  69         "jmp     @r0         \n"
  70         "mov.l   @%0+,r15    \n"
  71         : : "r"(loadaddress) : "r0"
  72     );
  73 }