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

[Chris Wilson]

Hi Umamaheswararao,

> 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

You are using signed chars, and they are being sign-extended to signed 
ints, which fills the remaining (upper) bits with 1's. When formatted as 
hex, they no longer fit into two characters, because the upper bits are 
not zeroes. So printf prints the full 32 bits.

Try using "unsigned char *s" in the prototype instead of just "char *s" 
and see if that helps.

Cheers, Chris.
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