On Wed, Mar 06, 2002 at 04:54:38PM -0800, Derek Peschel wrote:
> On Wed, Mar 06, 2002 at 01:42:38AM -0500, der Mouse wrote:
> > > how cross compiler generate 36-bit code on 32-bit machine?
> > 
> > Same way any foreign code is generated - mostly up to the assembler and
> > linker.  Define a way of representing 36-bit words (as, say, 5 8-bit
> > bytes with 4 bits wasted, or two 36-bit words in 9 8-bit bytes, or even
> > in extremis one 36-bit word stored in a 64-bit space with 28 bits of
> > padding).  Setting up the first boot may be a bit interesting,
> > depending on the boot methods and media, but that's about it.
> 
> The designers of FTP already solved that problem.  If a file contains
> 8-bit bytes, you can transfer it between a 16- or 32-bit machine and a 36-bit
> machine.  Probably the same is true for files containing 36-bit words.
> And it may even be true for word sizes other than 36.

What about 18 bit words?

The only system I had anything to do with (in this case reading
mag tapes it had written) that had 18/36 bit words used 6 bit
characters with an EBCDIC sytle encoding - think it was a UNIVAC.
The system words were written to 9 track (8 + parity) mag tape
without any wasted space - so one mag tape 'byte' could hold
parts of 2 different 36 bit words.  Fortunately the characters
were sensibly ordered (as if the system had 24 bit words).

	David

-- 
David Laight: david@l8s.co.uk