Subject: Re: Data format compatibility: old NetBSD/arm32, NetBSD/arm 26 vs.
To: Ignatios Souvatzis <ignatios@theory.cs.uni-bonn.de>
From: Ben Harris <bjh21@netbsd.org>
List: port-arm
Date: 10/29/2002 13:58:45
On Tue, 29 Oct 2002, Ignatios Souvatzis wrote:

> I'm trying to make pvm work^H^H^H^Hcompile again on Sharks.
>
> Is NetBSD/arm data format compatible to old NetBSD/arm32?

No, but the only change I'm aware of is that double-precision floating
point numbers are stored with native word-order rather than with
big-endian word order and native byte order within words.

> Is NetBSD/arm on 32 bit data format compatible to NetBSD/acorn26?

Yes, with the possible exception of a few kernel-internal structures.

When ARM finally finish the EABI, NetBSD is likely to transition to using
it.  At the moment, I'm aware of two differences between the data format
specified by the EABI and our current practice:

1: EABI requires the equivalent of -fpacked-enums

2: EABI requires that 8-byte values (double and long long) be 8-byte
   aligned.

> I want to decide whether it will NETBSDARM32 on all of them, or whether
> I need to create NETBSDARM26 and NETBSDARM in addition.

I think you need NETBSDARM and NETBSDARM32.  Presumably once we're using
EABI, we can use a value that's shared with all other EABI users.

-- 
Ben Harris                                                   <bjh21@netbsd.org>
Portmaster, NetBSD/acorn26           <URL:http://www.netbsd.org/Ports/acorn26/>