Subject: Re: ARM9 Endian mode
To: port-arm <>
From: Snorlax <>
List: port-arm
Date: 01/28/2004 10:41:01
> > I noticed that on some of the Intel XScale processors only Big endian =
> > mode is allowed, so I figure the dual compatible endian mode processors
> > has to do some conversion internally in one of the modes not native to =
> > the execution unit.
> >
> > Filip
> As long as a processor is designed in truly straight RISC discipline,
> is no chance to constraint endianess inside processor core.  The core
itself can
> be designed endian-neutral, i.e., no hardwired endianess and "incore
> conversion" back-and-forth.  Mixed endianness does matter at data path
> outside of core, at SoC internal-connect or at bus/peripheral-connect.
> Sometimes it's hard to keep entire hardware design endian-neutral, and
> more-or-less endian conversion efforts must be done either by hardware
> circuit design or device driver software.  Making XScale big-endian only
> can not wipe out endian conversion in practice and the decision was made
> by other reason(s) than "performance penalty."
> Toru Nishimura/ALKYL Technology

Thanks to all of you for clearing up issue for me.