applications compiled with mips16 ISA

applications compiled with mips16 ISA

[Pichai Raghavan]

Hi,

Has anyone put MIPS16 based applications on Linux 2.4.2 kernel? We 
want to use this to get more flash storage but unaware of the 
issues behind this. For ex: how will the loader work; will shared 
libraries compiled with MIPS16 work with MIPS32 applications. Can 
anyone thow light on this topic or point to us to some relevant 
documentation?

Thanks in advance
Raghav

Re: applications compiled with mips16 ISA

[Ralf Baechle]

On Fri, Dec 20, 2002 at 02:24:59PM -0000, Pichai  Raghavan wrote:

> Has anyone put MIPS16 based applications on Linux 2.4.2 kernel? We 
> want to use this to get more flash storage but unaware of the 
> issues behind this. For ex: how will the loader work; will shared 
> libraries compiled with MIPS16 work with MIPS32 applications. Can 
> anyone thow light on this topic or point to us to some relevant 
> documentation?

Linux running on MIPS16 CPUs has been used to verify CPU designs.  So
all the fundamental problems have been solved.  However there's no
application or library support, so you'd be pretty much alone.  The
general assumption is that MIPS16 systems in general are too small to
be sensibly used with Linux so there is no support for MIPS16 ASE.
Since MIPS16 is just an extension on top of another instructions set
such as MIPS32 there is nothing that prevents you from using just
that instruction set only, you'd loose the benefits of MIPS16 that
way.

  Ralf

Re: applications compiled with mips16 ISA

[Dominic Sweetman]

> Has anyone put MIPS16 based applications on Linux 2.4.2 kernel? We 
> want to use this to get more flash storage...

Linux applications and libraries require position-independent code.
gcc cannot yet generate PIC MIPS16 code.  We've considered fixing it
to do so for test purposes, but the code will be awful and much of the
MIPS16 code size reduction will be lost.

You'd surely do better to use software compression to reduce the size
of the code in your flash memory.

-- 
Dominic Sweetman
MIPS Technologies
The Fruit Farm, Ely Road, Chittering, CAMBS CB5 9PH, ENGLAND
phone +44 1223 706205/fax +44 1223 706250/swbrd +44 1223 706200
http://www.algor.co.uk