Accessing odd bytes

[Robert Schwebel <robert@schwebel.de>]

I have a strange effect on an embedded system (AMD Elan SC410,
Linux-2.4.18) while accessing a static RAM.  The RAM is mapped to the bus
at 0x0200'0000. If I map it to user space this way: 

  pSRAM  = (unsigned short *)mmap(0, 0x00040000, PROT_READ + PROT_WRITE, MAP_SHARED, FD, 0x2000000);

and fill it like this: 

  pByte=(char*)pSRAM;
  for (i=0; i<10; i++) {
    *pByte++=(char)i;
  }

  pByte=(char*)pSRAM;
  for (i=0; i<10; i++) {
    printf("i: %02i -> %03i\n", i, *pByte++);
  }

I see a mirroring effect: 

  i: 00 -> 001
  i: 01 -> 001
  i: 02 -> 003
  i: 03 -> 003
  i: 04 -> 005
  i: 05 -> 005
  i: 06 -> 007
  i: 07 -> 007
  i: 08 -> 009
  i: 09 -> 009

Now I'm wondering how the kernel/processor handles odd byte access
exceptions. Can anybody give me a pointer where I could search or what my
problem could be? 

Robert
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