Subject: Re: Data format compatibility: old NetBSD/arm32, NetBSD/arm 26
To: David Laight <>
From: Richard Earnshaw <>
List: port-arm
Date: 10/29/2002 15:27:43
> > 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.
> Ah - so they are now not in the ARM 'native' format for 64bit
> FP values? (IIRC one of the early arm cpus had hardware FP that used
> this mixed byte order.)
> Did ARM change their ABI?

Yes, the new VFP hardware uses 'pure-endianness' for doubles.

So they are still in native format, just a different native format.  Going 
forward it was agreed taht this was the best choice, given that the 
previous ABI never made any real use of the FPA.


PS.  The way things are shaping up on the EABI specification, it should be 
possible to have VFP accelerated routines that are completely compatible 
with the soft-call interface.  More details will follow when they