[Qemu-devel] Printing bogus values in ne2000_asic_ioport_read()/ ne2000_receive()

[Umamaheswararao Karyampudi]

Hi,
I am using QEMU in one of my research projects. I landed in a problem where I see bogus numbers being printed when I printed the packet/each word that is received from ne2000.

In ne2000_receive(), I copied the packet received to a static char [] and printed the packet using
 static void print_packet(char *s, int len)
{
  int i,j;
  for (i=0;i<len;i++) {
      if (i%20 == 0)
          printf("\n");
      printf("%02x ", s[i]);
  }
          printf("\n");
}
And some bytes it prints as fffffffff<last byte> instead of just the last byte. 
For eg: 
52 54 00 12 34 56 00 ffffffff 4f 0a 46 05 08 00 45 00 00 ffffff80 00 00
40 00 40 01 ffffffbc 2b ffffffc0 ffffffa8 fffffffe fffffffe ffffffc0 ffffffa8 ff

Similarly in ne2000_asic_ioport_read(), I print each word that
 is read from NetDriverState.s->mem using the following -
printf("\n %02x %02x", (char)(ret &0xff), (char) ( (ret >> 8) && 0xff));
And occasionally I see the 4 bytes printed instead of 1 byte for each value.

Any reason why it happens? Also, ne2000_asic_ioport_read(), reads 6 bytes before reading actual packet? I can think of 4 bytes for CRC but not for the remaining 2 bytes  - eg - If pak is -
52 54 00 12 34 56 00 ffffffff 4f 0a 46 05 08 00 45 00 00 ffffff80 00 00
40 00 40 01 ffffffbc 2b 
In asic_ioport_read() -
rdw 01 59
rdw 92 00
rdw 52 54
rdw 52 54
rdw 00 12
rdw 34 56

Anyhelp is greatly appreciated.

Thanks
Uma

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