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  * All files in this archive are subject to the GNU General Public License.
  17  * See the file COPYING in the source tree root for full license agreement.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23
  24 #include "uclimage.h"
  25
  26 #define ICODE_ATTR __attribute__ ((section (".icode")))
  27
  28 /* Symbols defined in the linker script */
  29 extern char iramcopy[], iramstart[], iramend[];
  30 extern char stackend[];
  31 extern char loadaddress[], dramend[];
  32
  33 /* Prototypes */
  34 extern void start(void);
  35
  36 void main(void) ICODE_ATTR;
  37 int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
  38                            unsigned long *dst_len) ICODE_ATTR;
  39
  40 /* Vector table */
  41 void (*vbr[]) (void) __attribute__ ((section (".vectors"))) =
  42 {
  43     start, (void *)stackend,
  44     start, (void *)stackend,
  45             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,
  46     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,
  47 };
  48
  49 /** All subsequent functions are executed from IRAM **/
  50
  51 /* Thinned out version of the UCL 2e decompression sourcecode
  52  * Original (C) Markus F.X.J Oberhumer under GNU GPL license */
  53 #define GETBIT(bb, src, ilen) \
  54     (((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)
  55
  56 int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
  57                            unsigned long *dst_len)
  58 {
  59     unsigned long bb = 0;
  60     unsigned ilen = 0, olen = 0, last_m_off = 1;
  61
  62     for (;;)
  63     {
  64         unsigned m_off, m_len;
  65
  66         while (GETBIT(bb,src,ilen))
  67             dst[olen++] = src[ilen++];
  68
  69         m_off = 1;
  70         for (;;)
  71         {
  72             m_off = m_off*2 + GETBIT(bb,src,ilen);
  73             if (GETBIT(bb,src,ilen))
  74                 break;
  75             m_off = (m_off-1)*2 + GETBIT(bb,src,ilen);
  76         }
  77         if (m_off == 2)
  78         {
  79             m_off = last_m_off;
  80             m_len = GETBIT(bb,src,ilen);
  81         }
  82         else
  83         {
  84             m_off = (m_off-3)*256 + src[ilen++];
  85             if (m_off == 0xffffffff)
  86                 break;
  87             m_len = (m_off ^ 0xffffffff) & 1;
  88             m_off >>= 1;
  89             last_m_off = ++m_off;
  90         }
  91         if (m_len)
  92             m_len = 1 + GETBIT(bb,src,ilen);
  93         else if (GETBIT(bb,src,ilen))
  94             m_len = 3 + GETBIT(bb,src,ilen);
  95         else
  96         {
  97             m_len++;
  98             do {
  99                 m_len = m_len*2 + GETBIT(bb,src,ilen);
 100             } while (!GETBIT(bb,src,ilen));
 101             m_len += 3;
 102         }
 103         m_len += (m_off > 0x500);
 104         {
 105             const unsigned char *m_pos;
 106             m_pos = dst + olen - m_off;
 107             dst[olen++] = *m_pos++;
 108             do dst[olen++] = *m_pos++; while (--m_len > 0);
 109         }
 110     }
 111     *dst_len = olen;
 112
 113     return ilen;
 114 }
 115
 116 #define ALIGNED_IMG_SIZE ((sizeof(image) + 3) & ~3)
 117 /* This will never return */
 118 void main(void)
 119 {
 120     unsigned long dst_len; /* dummy */
 121     unsigned long *src = (unsigned long *)image;
 122     unsigned long *dst = (unsigned long *)(dramend - ALIGNED_IMG_SIZE);
 123
 124     do
 125         *dst++ = *src++;
 126     while (dst < (unsigned long *)dramend);
 127
 128     ucl_nrv2e_decompress_8(dramend - ALIGNED_IMG_SIZE, loadaddress, &dst_len);
 129
 130     asm(
 131         "mov.l   @%0+,r0     \n"
 132         "jmp     @r0         \n"
 133         "mov.l   @%0+,r15    \n"
 134         : : "r"(loadaddress) : "r0"
 135     );
 136 }