[Mspgcc-users] shift operation problem with "unsigned long"

[Peter Mueller]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi all,
I'm writing an interface to a chip which provides its data via a shift 
register.
It looks like that shifting ones in the lower 16Bit of an unsigned long 
works fine. A bit shifted into the higher 16 Bits just gets lost. Is 
this a known issue or maybe a sw-error on my side that I've just 
overseen?

My code looks in principle like:

- -----
  unsigned long data=0;
  unsigned char n;

  for (i=0; i<25; i++){

    // set clock high
    n = P1IN & 0x1;
    // set clock low
    if(n){
      data |= 1;  // shift in a one
      data << 1;
    }else{
      data <<1;  // shift in a zero
    }

   printf("%x ", data);
  }
- ----

For a given input stream the output looks like: 2 4 8 10 20 40 82 106 
20c 418 830 1060 20c0 4180 8300 600 c00 1800 3000 6000 c000 8000 0 0

One can see that after shifting the next bit into 0x8000 the result is 
0 but should be 0x10000.

Thanks for your help,
Peter

P.S: I use msp430-gcc version 3.2.3 on a windows box



Peter Mueller
peter.o.muel...@gmx.de
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.3 (Darwin)

iD8DBQFBti/kUzCcwYQMTJoRAq8SAJ9wGEdP8WdecbhenUf4QXGWvg/+fQCfXyWu
Bcls7NaUVSda+E0cH0HghPY=
=wx9e
-----END PGP SIGNATURE-----