Subject: Re: NetBSD/pdp10 ?
To: None <tech-kern@netbsd.org>
From: Derek Peschel <dpeschel@eskimo.com>
List: tech-kern
Date: 03/06/2002 16:54:38
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.

Using the same encodings might make the "first boot" problem a lot easier
to solve.

-- Derek